noun
half a ken (approx. 0.9 m)
Traditional Japanese unit of length; one ken (間) is about 1.818 m, so half a ken is roughly 0.9 m. Used in architecture and carpentry contexts.
See also: 一間
この柱の間隔は間中になっている。
The spacing between these pillars is half a ken.
noun
half-sized tatami mat
A tatami mat that is half the standard length; used in traditional Japanese rooms where a full mat would not fit.
部屋の隅に間中の畳が敷いてある。
A half-sized tatami mat is laid in the corner of the room.
一間 means one ken (about 1.818 m), while 間中 is half that length.
Compound of 間 (ken, a traditional unit of length) and 中 (naka, middle/half), indicating half a ken. The alternate spelling 間半 uses 半 (half) directly.