also: じ
Refers to the movable bridge of a koto or similar stringed instrument; also used as a suffix in compound terms like 琴柱 (ことじ).
I tune the koto by moving its bridges.
This bridge is made of ivory.
Only with reading ちゅう
Used in geometry and technical contexts; reading is always ちゅう. Often appears as a suffix in words like 円柱 (cylinder) and 角柱 (prism).
Calculate the volume of the cylinder.
A triangular prism has five faces.
utility pole; power pole; telephone pole
prop; support; brace
spinal column; spine; vertebral column
cylinder; column; shaft · round pillar (architecture)
stone pillar; stone column
prism · polygonal pillar; square pillar · bamboo
columnar; pillar-shaped
gatepost; gate pier
iron pole; steel column
triangular prism
marker post; signpost; guide pole · levelling pole; surveying rod
central pillar; main pillar · principal post; backbone; key figure
bollard; bitt; mooring post
endostyle · interior column; inner pillar
colonnade; row of columns
pillars supporting heaven
cylinder; prism
pillared corridor; colonnade
pillar; cornerstone
plinth; column base
posthole
Standard kanji spelling for both senses; reading ちゅう is the primary reading for the musical bridge sense and the only reading for the geometric sense.
Alternate reading used only for the musical bridge sense; じ is less common than ちゅう.
The kanji 柱 originally means 'pillar' or 'post'. Its use for a koto bridge likely comes from the visual similarity of the small standing pieces to pillars. The geometric sense is a later extension, probably from the idea of a solid standing shape.