"in a glow, glowing," 1817 (in Coleridge), from a- (1) + glow (v.). Figurative sense of "flushed with pleasurable excitement" is from 1830.
a house aglow with lights
agitprop
Aglaia
agleam
aglet
aglimmer
aglow
agnail
Agnes
agnostic
agnosticism
Agnus Dei