Privative a

The privative a (also known as privative alpha or α privativum) is the prefix a-, called a privative, which expresses negation (e.g. a-theism, ). Originally described for the grammar of Ancient Greek, it goes back to a PIE syllabic nasal *n̥-, the zero ablaut grade of the negation *ne, i.e. "n" used as a vowel, as in some English pronunciations of "button". For this reason, it appears as an- before vowel (e.g. an-alphabetism, an-esthesia, an-archy). The same prefix appears in Sanskrit, also as a-, an-. In Latin, the cognate prefix is in-, and in West Germanic languages (including English) it is un-. 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 uses the etymologically related ó.
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