Forms nouns: condition (of), state (of); As a prefix, a- is a privative (negating) morpheme meaning “without,” “not,” or “lacking” — indicating the absence of a structure, function, or condition. It attaches to Greek-derived roots. When the root begins with a vowel, it typically becomes an- to ease pronunciation. As a suffix, -a serves primarily as a grammatical/nominative ending in Latin and Greek nouns (especially neuter plural Latin forms and feminine singular forms), giving medical terms their standard noun form rather than carrying independent clinical meaning.
greek a- / an- — the Greek alpha privative, one of the oldest and most productive prefixes in medical terminology. Parallel to Latin in- (also meaning “not/without”). The suffix use derives from Latin and Greek nominative noun endings