Middle English bon, from Old English ban "bone, tusk, hard animal tissue forming the substance of the skeleton; one of the parts which make up the skeleton," from Proto-Germanic *bainan (source also of Old Frisian and Old Saxon ben, Old Norse bein, Danish ben, German Bein). Absent in Gothic, with no cognates outside Germanic (the common PIE root is *ost-); the Norse, Dutch, and German cognates also mean "shank of the leg," and this is the main meaning in Modern German, but English seems never to have had this sense.

To work (one's) fingers to the bone is from 1809. To have a bone to pick (1560s) is an image of a dog struggling to crack or gnaw a bone (to pick a bone "strip a bone by picking or gnawing" is attested from late 15c.); to be a bone of contention (1560s) is of two dogs fighting over a bone; the images seem to have become somewhat merged. Also compare bones.

Bone-china, which is mixed with bone-dust, is so called by 1854. Bone-shaker (1874) was an old name for the early type of bicycle, before rubber tires.

"leg of a human or animal," especially "the part of the leg from the knewe to the ankle," Old English sceanca "leg, shank, shinbone," specifically, the part of the leg from the knee to the ankle, from Proto-Germanic *skunkia-, perhaps literally "that which bends," from PIE root *skeng- "crooked" (source also of Old Norse skakkr "wry, distorted," Greek skazein "to limp").

From late 15c. as "straight part of a nail or pin." As "part of an instrument, tool, etc., which connects the acting part with the handle," from 1680s. The slang sense of "latter part or end of anything" is by 1828.

Jocular shank's mare "one's own legs as a means of transportation" is attested from 1774 (as shanks-naig).

Germanic cognates include Middle Low German schenke, German schenkel "shank, leg."

"swindler," originally especially in equestrian events, 1771, from black (adj.) + leg (n.), but the exact signification is uncertain.

The term implies the habitual frequenting of places where wagers are made and games of chance are played, and the seeking of subsistence by dishonorable betting, but does not always imply direct cheating. Sometimes contracted to leg. [Century Dictionary]

Used from 1865 of strike-breakers and workmen who refused to join trade unions.

also boot-leg, "upper part of the leg of a boot," 1630s, from boot (n.1) + leg (n.). As an adjective in reference to illegal liquor, 1889, American English slang, from the trick of concealing a flask of liquor down the leg of a high boot. Before that the bootleg was the place to secret knives and pistols. Extended to unauthorized music recordings, etc., by 1957.

"having the legs crossed" (usually of seated persons), 1520s; see cross- + leg (n.).

also dogleg, "bent like a dog's hind leg," 1843, earlier dog-legged (1703), which was used originally of a type of staircase which has no well hole and consists of two flights with or without winders. See dog (n.) + leg (n.).

late 15c., from fore- + leg (n.).

"an aid, a boost," 1837, from leg (n.) + up (adv.).

"having legs" (of a specified kind), usually in compounds, mid-15c., from leg (n.).

"extra outer covering to protect the leg," 1763, from leg (n.). Related: Leggings.