An alpha privative or, rarely, privative a (from Latin alpha prīvātīvum, from Ancient Greek α στερητικόν) is the prefix a- or an- (before vowels) that is used in Greek and in English words borrowed from Greek to express negation or absence, for example atypical, anesthetic, and analgesic.
Contents
It is derived from a Proto-Indo-European syllabic nasal *n̥-, the zero ablaut grade of the negation *ne, i.e. /n/ used as a vowel. For this reason, it usually appears as an- before vowels (e.g. an-alphabetism, an-esthesia, an-archy). It shares the same root with the Greek prefix nē or ne, in Greek νη or νε, that is also privative (e.g. ne-penthe).
Sanskrit
The same prefix appears in Sanskrit, also as a-, an-
Latin
In Latin, the cognate prefix is in-. The prepositional prefix in- is unrelated.
Germanic languages
In English and other West Germanic languages, the cognate is un- (or on-).
In North Germanic languages, the -n- has disappeared and Old Norse has ú- (e.g. ú-dáins-akr), Danish and Norwegian have u-, whereas Swedish uses o- (pronounced [u]), and Icelandic and Faroese use the related ó-.
Homonym
The prefix ἁ- ha- (also ἀ- a- from psilosis), copulative a, is nearly homonymous with privative a, but originates from Proto-Indo-European *sm̥.