A- or a- may refer to: ;A-hyphen *

A- (plane) An attack aircraft, strike aircraft, or attack bomber is a tactical military aircraft that has a primary role of carrying out airstrikes with greater precision than bombers, and is prepared to encounter strong low-level air defenses while pr ...

, a U.S. military aircraft prefix * Privative a, a prefix expressing negation *

Copulative a The copulative ''a'' (also ''a'' copulativum, ''a'' athroistikon) is the prefix ''ha-'' or ''a-'' expressing unity in Ancient Greek, derived from Proto-Indo-European *''sm̥-'', cognate to English ''same'' (see also Symbel).. An example is ''a-de ...

, a prefix expressing unification ;A-minus * A−, a blood type in the

ABO blood group system The ABO blood group system is used to denote the presence of one, both, or neither of the A and B antigens on erythrocytes. For human blood transfusions, it is the most important of the 43 different blood type (or group) classification system ...

A− (grade) This is a list of grading systems used by countries of the world, primarily within the fields of secondary education and university education, organized by continent with links to specifics in numerous entries. Africa Nigeria The choice of gr ...

, an educational grade in the letter-grading system, above B+ but below A

See also