noun
wheel hub; nave
Technical term for the central part of a wheel; rarely used in everyday Japanese. The reading こく is an alternative on-reading, but こしき is more common for this character.
轂は車輪の中心部で、スポークが集まる部分です。
The hub is the central part of a wheel where the spokes meet.
Kana spelling is more practical for learners and avoids the obscure kanji.
The loanword ハブ is the common modern term for 'hub' in mechanical and IT contexts, while 轂 is a rare, traditional kanji term.
The kanji 轂 is a phono-semantic compound with 車 (vehicle) and 殻 (shell/husk), referring to the hub that encloses the axle. The reading こしき is the native Japanese kun'yomi, while こく is the Sino-Japanese on'yomi.