両

Ryōchiku (the two former provinces of Chikuzen and Chikugo)

biological parents

both sides of the chest

both breasts

Mahjong

inferior double-sided shape; incomplete chow that may be completed by one of eight tiles of two types, two of which tiles are already consumed by the hand's pair; tile pattern composed of a complete chow and an additional tile of its lowest or highest rank (e.g. 3345 or 3455)

parents-in-law

Go (game)

double sente; move that is sente for either player

Go (game)

double gote; move that is gote for either player

being accomplished in both the literary and military arts

doing well in both school and sports

double-edged sword

Idiomatic expression

two blessings at once; flanked by two beautiful women

arguments for and against; pros and cons; mixed reception; mixed reviews

killing two birds with one stone; serving two ends

within the next couple of days; in a day or two

in a quarrel, both parties are to blame

androgynous; hermaphroditic

amphibious

emergency vehicle

star (actor); prima donna; leading figure

bilateral relations; relationship between two countries

both houses of the Diet

women-only carriage (e.g. on a train)

double-sword fencing; two-sword fencer

being skilled in two fields; (an) expert in two fields

liking both alcohol and sweets; person who likes alcohol and sweets equally well

Colloquial

bisexual (person)

railway vehicle; railroad vehicle

operations (a strategy) on two fronts; two-pronged strategy