active (given to action)

concentration, density / (set theory) cardinality

(typography) the distribution of any plural number of lines and leads so that they fit a specific number of ems, for example, 2 or 3 lines within 4 ems

(grammar) active voice

union, combination / (mathematics) congruence (of matrix, integer, shape)

(archaic) one who travels: a traveler

(photography, computer graphics) resolution

(shogi) free king, queen (a piece in chu shogi, dai shogi and larger shogi variants)

(obsolete) Oakland (a city in Alameda, California, United States) / (historical) Ryukyuan royal administration (government)

crown prince