Crasis (; from the Greek , "mixing", "blending") is a type of contraction in which two vowels or diphthongs merge into one new vowel or diphthong, making one word out of two. Crasis occurs in Portuguese, French and Arabic as well as in Ancient Greek, for which it was first described.
In some cases, as in the French examples below, crasis involves the grammaticalization of two individual lexical items into one, but in other cases, like in the Greek examples, crasis is the orthographic representation of the encliticization and vowel reduction of one grammatical form with another. The difference between the two is that the Greek examples involve two grammatical words and a single phonological word and the French examples involve a single phonological word and grammatical word.
In Ancient Greek, a coronis (? kor?nís "curved"; plural kor?nídes) marks the vowel from crasis. In ancient times, it was an apostrophe placed after the vowel (), but it is now written over the vowel ?, and it is identical to smooth breathing in Unicode. (For instance, ? uses the character ἀ GREEK SMALL LETTER ALPHA WITH PSILI; psili means smooth breathing.) Unlike a coronis, smooth breathing never occurs on a vowel in the middle of a word (although it occurs on doubled rho: pyrrhos).
The article undergoes crasis with nouns and adjectives that start with a vowel:
undergoes crasis with the first-person singular pronoun and produces a long vowel:
In modern monotonic orthography, the coronis is not written.
In French, the contractions of determiners are often the results of a vocalisation and a crasis:
This section needs expansion. You can help by adding to it. (August 2007)
The most frequently observed crasis today is the contraction of the preposition a ("to" or "at") with the feminine singular definite article a ("the"), indicated in writing with a grave accent, or the masculine singular definite article o (also "the"). For example, instead of *Vou a a praia ("I go to the beach"), one says Vou à praia ("I go to-the beach"). The contraction turns the clitic a into the stressed word à. Meanwhile, a person going to a bank, a supermarket or a marketplace would say Vou ao banco, Vou ao supermercado or Vou à feira, respectively.
Crasis also occurs between the preposition a and demonstratives: for instance, when the preposition precedes aquele(s), aquela(s) (meaning "that", "those", in different genders), they contract to àquele(s), àquela(s). The accent marks a secondary stress in Portuguese.
In addition, the crasis à is pronounced lower as than the article or preposition a, as , in the examples in standard European Portuguese, but the qualitative distinction is not made by most speakers in Brazilian Portuguese (some dialects, as Rio de Janeiro's fluminense, are exceptions and make the distinction).
Crasis is very important, as it can change the meaning of a sentence:
These rules determine whether the crasis always apply, or whether one may use the contraction à (with an accent) instead of the preposition a (without an accent):
Replace the preposition a by another preposition, as em ("in") or para ("to"). If, with replacement, the definite article a ("the") is still possible, crasis applies:
If the nominal complement is changed, after "a", from a feminine noun to a masculine noun and it is now necessary to use 'ao' (used naturally by native speakers), crasis applies:
The grave accent is never used before masculine words (nouns, pronouns, etc.); verbs; personal pronouns; numerals, plural nouns without the use of the feminine plural definite article as ("the"); city names that do not use a feminine article; the word casa ("house") if it has the meaning of one's own home;/the word terra ("earth") when it has the meaning of soil; and indefinite, personal, relative or demonstrative pronouns (except the third person and aquele(s) or aquela(s)); between identical nouns such as dia a dia "day by day", "everyday", "daily life", gota a gota "dropwise", "drip", and cara a cara "face to face"; and after prepositions. Here are exceptions:
É preciso declarar guerra à guerra! (It is necessary to declare war on war!)
É preciso dar mais vida à vida. (It is necessary to give more life to life.)
The grave accent is optional in the following cases:
Refiro-me [à/a] Fernanda. (I am referring to Fernanda.)
Dirija-se [à/a] sua fazenda. (Go to your [own] farm.)
Dirija-se até [à/a] porta. (Go by that door.)
Eu fui até [à/a] França de carro. (I traveled to France by car.)