noun
cycloidal gear teeth
Technical term in mechanical engineering referring to gear teeth with a cycloidal profile, used in some precision or high-torque applications.
この時計にはサイクロイド歯車が使われている。
This clock uses cycloidal gear teeth.
Involute gear teeth are more common in modern machinery; cycloidal teeth are used in some watches and specialized applications.
From English 'cycloid' plus Japanese 歯車 (gear).