The word "moustache" is French, and is derived from the Italian moustacio (fourteenth century), dialectal mostaccio (16th century), from Medieval Latin moustaccium (eighth century), Medieval Greek ? (moustakion), attested in the ninth century, which ultimately originates as a diminutive of Hellenistic Greek (mustax, mustak-), meaning "upper lip" or "facial hair", probably derived from Hellenistic Greek (mullon), "lip".
Research done on this subject has noticed that the prevalence of moustaches and facial hair in general rise and fall according to the saturation of the marriage market. Thus, the nuances of the density and thickness of the moustache or beard may help to convey androgen levels or age.
Moustache popularity in the west peaked in the 1880s and 1890s coinciding with a popularity in the military virtues of the day.
Various cultures have developed different associations with moustaches. For example, in many 20th-century Arab countries, moustaches are associated with power, beards with Islamic traditionalism, and lack of facial hair with more liberal, secular tendencies. In Islam, trimming the moustache is considered to be a sunnah and mustahabb, that is, a way of life that is recommended, especially among Sunni Muslims. The moustache is also a religious symbol for the male followers of the Yarsan religion.
Shaving with stone razors was technologically possible from Neolithic times. A mustache is depicted on a statue of the 4th Dynasty Egyptian prince Rahotep (c. 2550 BC). Another ancient portrait showing a shaved man with a moustache is an ancient Iranian (Scythian) horseman from 300 BC.
In ancient China facial hair and the hair on the head were traditionally left untouched because of Confucian influences. 
Moustaches can be tended through shaving the hair of the chin and cheeks, preventing it from becoming a full beard. A variety of tools have been developed for the care of moustaches, including safety razors, moustache wax, moustache nets, moustache brushes, moustache combs and moustache scissors.
In the Middle East, there is a growing trend for moustache transplants, which involves undergoing a procedure called follicular unit extraction in order to attain fuller, and more impressive facial hair.
The longest moustache measures 4.29 m (14 ft) and belongs to Ram Singh Chauhan (India). It was measured on the set of the Italian TV show "Lo Show dei Record" in Rome, Italy, on 4 March 2010.
Other types of moustache include:
"Fu Manchu" moustache style
"Handlebar" moustache style
"Horseshoe" moustache style
"Pencil" moustache style
"Toothbrush" moustache style
Like many other fashion trends, the moustache is subject to shifting popularity through time. Though modern culture often associates moustaches with men of the Victorian Era, Susan Walton shows that at the start of the Victorian Era facial hair was "viewed with distaste" and that the moustache was considered the mark of an artist or revolutionary, both of which remained on the social fringe at the time. This is supported by the fact that only one Member of Parliament sported facial hair from the years 1841-47. However, by the 1860s, this had changed and moustaches became wildly popular, even among distinguished men, but by the end of the century, facial hair became passé once more. Though one cannot be entirely sure as to the cause of such changes, Walton speculates that the rise of the facial hair trend was due largely in part to the impending war against Russia, and the belief that moustaches and beards projected a more 'manly' image, which was brought about by the so-called 'rebranding' of the British military and the rehabilitation of military virtues. Moustaches became a defining trait of the British soldier, and until 1916, no enlisted soldier was permitted to shave his upper lip. However, the next generation of men perceived facial hair, such as moustaches, to be an outdated emblem of masculinity and therefore there was a dramatic decline in the moustache trend and a clean-shaven face became the mark of a modern man.
According to a study performed by Nigel Barber, results have shown a strong correlation between a good marriage market for women and an increased number of moustaches worn by the male population. By comparing the number of males pictured in Illustrated London News sporting a moustache against the ratio of single women to single men, the similar trends in the two over the years would suggest that these two factors are correlated. Barber suggests that this correlation may be due to the fact that men with moustaches are perceived to be more attractive, industrious, creative, masculine, dominant and mature by both men and women, as supported by the research conducted by Hellström and Tekle. Barber suggests that these perceived traits would influence a woman's choice of husband as they would suggest a high reproductive and biological qualities, and a capacity to invest in children, so when males must compete heavily for marriage they are more likely to grow a moustache in an attempt to project these qualities. This theory is also supported by the correlation between beard fashion and women wearing long dresses, as shown by Robinson's study, which then relates to the correlation between dress fashion and the marriage market, as shown in Barber's 1999 study.
The moustache and other forms of facial hair are globally understood to be signs of the post-pubescent male; however, those with moustaches are perceived to be older than those who are clean-shaven of the same age. This was determined by manipulating a photo of six male subjects, with varying levels of baldness, to have moustaches and beards and then asking undergraduate college students to rate both the photos of the men with facial hair and without facial hair in terms of social maturity, aggression, age, appeasement, and attractiveness. Regardless of how bald the subject was, the results found in relation to the perception of moustaches remained constant. Although males with facial hair were perceived, in general, to be older than the same subject pictured without facial hair, the moustached subjects were also perceived to be far less socially mature. The decreased perception of social maturity of the men with moustaches may partially be due to the increase in the perception of aggression in the moustachioed men, as aggression is incompatible with social maturity.
In a study performed by J. A. Reed and E. M. Blunk, persons in management positions were shown to positively perceive, and therefore be more likely to hire, men with facial hair. Although men with beards over all scored better than men with only moustaches, the moustached men scored much higher than those men who were clean-shaven. In this experiment, 228 persons, both male and female, who held management positions that made hiring decisions were shown ink sketches of six male job applicants. The men in these ink sketches ranged from clean-shaven, to moustachioed, to bearded. The men with facial hair were rated higher by the employers on aspects of masculinity, maturity, physical attractiveness, dominance, self-confidence, nonconformity, courage, industriousness, enthusiasm, intelligence, sincerity, and general competency. The results were found to be fairly similar for both female and male employers, which Reed and Blunk suggest would imply that gender does not factor into one's perceptions of a moustache on a male applicant. However, Blunk and Reed also stipulate that the meaning and acceptability of facial hair does change depending on the time period. However, the studies performed by Hellström & Tekle and also the studies performed by Klapprott would suggest that moustaches are not favourable to all professions as it has been shown that clean-shaven men are seen as more reliable in roles such as salesmen and professors. Other studies have suggested that acceptability of facial hair may vary depending on culture and location, as in a study conducted in Brazil, clean-shaven men were preferred by personnel managers over applicants who were bearded, goateed, or moustached.
African-American men tend to have a higher percentage of wearing a mustache compared to Caucasian men in the United States: "A far greater percentage of African-American males than white males wear mustaches today and have always worn mustaches."
In Western culture, it has been shown that women dislike men who displayed a visible moustache or beard, but preferred men who had a visible hint of a beard such as stubble (often known as a five-o-clock shadow) over those who were clean-shaven. This supports the idea that in Western culture, females prefer men who have the capability to cultivate facial hair, such as a moustache, but choose not to. However some researchers have suggested that it is possible that in ecologies in which physical aggressiveness is more adaptive than cooperation, bearded men might be preferred by women. However, varying opinion on moustaches is not reserved to international cultural differences as even within the US, there have been discrepancies observed on female preference of male facial hair as Freedman's study suggested that women studying at the University of Chicago preferred men with facial hair because they perceived them to be more masculine, sophisticated and mature than clean-shaven men. Similarly, a study performed by Kenny and Fletcher at Memphis State University, which is largely a commuter school and usually is regarded as more conventional than the University of Chicago, suggested that men with facial hair such as moustaches and beards, were perceived as stronger and more masculine by female students. However, the study performed by Feinman and Gill would suggest that this reaction to facial hair is not nationwide, as women studying in the state of Wyoming showed a marked preference for clean-shaven men over men with facial hair. Some accredit this difference to the difference between region, rurality, and political and social conservatism between the various studies. Thus it can be seen that even within the US, there are slight variations in the perceptions of moustaches.
In addition to various cultures, the perception of the moustache is also altered by religion as some religions support the growth of a moustache or facial hair in general, whereas others tend to reject those with moustaches, while many churches remain somewhat ambivalent on the subject.
While Amish men grow beards after marriage and never trim them, they eschew moustaches and continue shaving their upper lips. This is rooted in a rejection of the German military fashion of sporting moustaches, which was prevalent at the time of the Amish community's formation in Switzerland; hence serving as a symbol of their commitment to pacifism.
Though it is never explicitly stated by The Church of Jesus Christ of Latter-day Saints that all male members must be clean-shaven, within Mormon circles it is often considered "taboo" for men to have moustaches as the missionaries of the church are required to be clean-shaven as well as the honor code of Brigham Young University requiring students to have similar grooming standards. This has become somewhat of a social norm within the church itself. This often leads those members who do choose to wear moustaches feel somewhat like they do not quite fit the norm, and yet in the studies shown done by Nielsen and White, these men reportedly do not mind this feeling and that is why they continue to grow their facial hair.
Even though facial grooming is not specifically mentioned within the Qur'an, numerous narrations of hadith (sayings of Muhammad) address personal hygiene, including facial hair maintenance. In one such example, Muhammad advised that men must grow beards, and as to moustaches, cut the longer hairs as to not let them cover the upper lips (as this is the Fitra--the origin). Thus, growing a beard while keeping the moustache short and trimmed is a well-established tradition in many Muslim societies.
The longest moustache measures 4.29 m (14 ft) and belongs to Ram Singh Chauhan of India. It was measured on the set of Lo Show dei Record in Rome, Italy, on 4 March 2010.
In some cases, the moustache is so prominently identified with a single individual that it could identify him without any further identifying traits. For example, Kaiser Wilhelm II's moustache, grossly exaggerated, featured prominently in Triple Entente propaganda. Other notable individuals are Hitler, Mugabe and Steve Harvey. In other cases, such as those of Charlie Chaplin and Groucho Marx, the moustache in question was artificial for most of the wearer's life.
They have also been used to make a social or political point as with:
Narrated Abu Huraira: The Prophet said "Five things are in accordance with the Fitra (i.e. the tradition of prophets): to be circumcised, to shave the pelvic region, to pull out the hair of the armpits, to cut short the moustaches, and to clip the nails.'