German, "family tree," especially of languages, 1939, from Stamm "tree, trunk" (see stem (n.)) + Baum "tree" (see beam (n.)).

"pivot on the end of a beam," c. 1400, from Old French gojon "pin, peg, spike" (13c.), perhaps somehow an altered sense of gudgeon (n.1).

also axletree, "bar or beam fitted crosswise under the body of a carriage and having wheels fitted to the ends," c. 1300; see axle (n.) + tree (n.).

"beam projecting from each side of the bows of a ship to hold the anchor away from the body of the ship," 1620s, from cat (n.) in some obscure sense + head (n.).

c. 1500, "beam or shaft of a barrow or sledge," also "a barrow or truck body" (1510s), Scottish, originally in reference to the iron trucks used in coal mines, probably from Middle Flemish tram "beam, handle of a barrow, bar, rung," a North Sea Germanic word of unknown origin.

The sense of "track for a barrow, tramway" is attested by 1826; that of "streetcar" is attested by 1879, short for tram-car "car used on a tramway" (1873).

"to weigh against with an equal weight; to serve as a counterpoise to," 1610s, from counter- + balance (v.), in reference to scales. Figurative use dates from 1630s. As a noun, from 1610s, "equal weight or power;" figuratively, "influence acting in opposition," from 1630s.

mid-15c., radiacion, "act or process of emitting light," from Latin radiationem (nominative radiatio) "a shining, radiation," noun of action from past-participle stem of radiare "to beam, shine, gleam; make beaming," from radius "beam of light; spoke of a wheel" (see radius).

Meaning "rays or beams emitted" is from 1560s. Meaning "divergence from a center" is 1650s. In modern physics, "emission or transmission of energy in the form of waves or particles," especially in reference to ionizing radiation, from early 20c.

pole used in housebuilding, especially as an object tossed in the Highland games, 1510s, from Gaelic cabar "pole, spar," cognate with Irish cabar "lath," Welsh ceibr "beam, rafter."

"main supporting wooden beam that carries flooring," 1610s, agent noun from gird, on notion of something that "holds up" something else. Used of iron bridge supports from 1853.

[structure that affords passage over a ravine or river] Middle English brigge, from Old English brycge, from Proto-Germanic *brugjo (source also of Old Saxon bruggia, Old Norse bryggja, Old Frisian brigge, Dutch brug, Old High German brucca, German Brücke), from PIE root *bhru "log, beam," hence "wooden causeway" (source also of Gaulish briva "bridge," Old Church Slavonic bruvuno "beam," Serbian brv "footbridge").

The original notion is of a beam or log laid down for crossing. Compare Old Church Slavonic mostu, Serbo-Croatian most "bridge," probably originally "beam" and a loanword from Germanic, related to English mast (n.1). For the vowel evolution, see bury.

The meaning "bony upper part of the nose" is from early 15c.; of stringed instruments from late 14c. The bridge of a ship (by 1843) originally was a "narrow raised platform athwart the ship whence the Captain issues his orders" [Sir Geoffrey Callender, "Sea Passages"].

Bridge in steam-vessels is the connection between the paddle-boxes, from which the officer in charge directs the motion of the vessel. [Smyth, "The Sailor's Word-book," 1867]