strut; short vertical post
A short vertical structural member, such as a stud in a wall or a post in a railing.
The short post of the stair railing is broken.
thickness (of a book minus the cover, a sheaf of paper, etc.)
Refers to the thickness of a stack of paper or the body of a book excluding the covers. Often used in printing and bookbinding contexts.
This book has a thickness of 3 centimeters.
In old documents, there are examples where the length of arrows is expressed in 'tsuka'.
short pillar between beam and ridge
sheaf of rice; bundle of rice plants
arrow length · bundle of arrows
sheaf of rice; bundle of rice plants
Standard kanji spelling for this reading.
Kana spelling is acceptable, especially to avoid confusion with 束 (そく) or 束 (たば).
The reading つか is native Japanese. The kanji 束 is used for its meaning of 'bundle' or 'bind', which extended to structural posts and thickness measurements. The archaic handbreadth unit likely derives from the width of a bundle of fingers.