あいくち

合口, 合い口: compatibility, rapport, or cooperativeness in anything done together with others

合口, 合い口: getting along well with others, affinity

合口, 合い口: the join or fit between stones or bricks in masonry or other wall building

合口, 合い口: the join or fit between a lid and a container

合口, 合い口: a style of constructing a 短刀 (tantō, “short sword; dagger”) without a crossguard, so that the hilt fits directly against the opening of the scabbard

匕首, 合口, 合い口: a specific type of dagger with no crossguard, where the hilt fits directly against the opening of the scabbard, often kept concealed in one's clothing