pitch circle, pitch line

Gearing: The circle of contact of a cog-wheel which meshes with a corresponding cog-wheel or rack. pitch-farthing, pitch-penny, s. The same as CHUCK-FARTHING (q. v.). "A couple of half-grown lads were playing at pitch farthing." -Hughes: Tom Brown at Oxford , ch. xix. *pitch-field, s. A pitched battle. pitch-line, s. [PITCH-CIRCLE.