camber (n.)

1708, "vaulted building; arched roof or ceiling," from Latin camera "a vault, vaulted room" (source also of Italian camera, Spanish camara, French chambre), from Greek kamara "vaulted chamber, anything with an arched cover," which is of uncertain origin. A doublet of chamber. Old Church Slavonic komora, Lithuanian kamara, Old Irish camra all are borrowings from Latin.

The word also was used from early 18c. as a short form of Modern Latin camera obscura "dark chamber" (a black box with a lens that could project images of external objects), contrasted with camera lucida (c. 1750, Latin for "light chamber"), which uses prisms to produce on paper beneath the instrument an image which can be traced of a distant object.

This sense was expanded to become the word for "picture-taking device used by photographers" (a modification of the camera obscura) when modern photography began c. 1840. The word was extended to television filming devices from 1928. Camera-shy is attested from 1890. Camera-man is from 1908.

1777, "a projecting part of a rotating machinery used to impart motion to another part," from Dutch cam "cog of a wheel," originally "comb," from Proto-Germanic *kambaz "comb," from PIE root *gembh- "tooth, nail." It is thus a cognate of English comb (n.). This might have combined with English camber "having a slight arch;" or the whole thing could be from camber. It converts regular rotary motion into irregular, fast-and-slow rotary or reciprocal motion. "The original method was by cogs or teeth fixed or cut at certain points in the circumference or disc of a wheel ..." [OED]. Cam-shaft attested from 1850.