Crasis

Crasis (/ˈkreɪsɪs/; from the Greek κρᾶσις, lit. 'mixing' or '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 (univerbation). Crasis occurs in many languages, including French, Italian, Portuguese, and Spanish; it was first described in Ancient Greek.

In some cases, as in the French examples, crasis involves the grammaticalization of two individual lexical items into one. However, in other cases, like in the Greek examples, crasis is the orthographic representation of the encliticization and the vowel reduction of one grammatical form with another. The difference between them is that the Greek examples involve two grammatical words and a single phonological word, but the French examples involve a single phonological word and grammatical word.

In both Ancient and Modern Greek, crasis merges a small word and long word that are closely connected in meaning.

In Ancient Greek, a coronis (κορωνίς korōnís "curved"; plural κορωνίδες korōnídes) marks the vowel from crasis. In ancient times, it was an apostrophe placed after the vowel (τα᾽μά), but it is now written over the vowel (τἀμά) and is identical to smooth breathing in Unicode. (For instance, τἀμά uses the character U+1F00 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 in a doubled rho: πύῤῥος pyrrhos.

The article undergoes crasis with nouns and adjectives that start with a vowel:

καί undergoes crasis with the first-person singular pronoun and produces a long vowel:

In the modern monotonic orthography, the coronis is not written.

In Italian, crasis occurs between the prepositions a, da, di, in, con, su, per and the singular masculine definite article il or in fewer cases with the plural masculine definite articles i and gli.