late 14c., metathesis of Old English þurh, from Proto-Germanic *thurx (source also of Old Saxon thuru, Old Frisian thruch, Middle Dutch dore, Dutch door, Old High German thuruh, German durch, Gothic þairh "through"), from PIE root *tere- (2) "to cross over, pass through, overcome." Not clearly differentiated from thorough until early Modern English. Spelling thro was common 15c.-18c. Reformed spelling thru (1839) is mainly American English.
indicating the sound of a muffled internal combustion engine, 1904, imitative. Applied to various engines or objects which make such a sound.
Middle English putten, from late Old English *putian, "to thrust, push, shove" (someone or something; a sense now obsolete), also "to move or a thing physically so as to place it in some situation," implied in putung "instigation, an urging," literally "a putting;" related to pytan "put out, thrust out" (of eyes), probably from a Germanic stem that also produced Danish putte "to put," Swedish dialectal putta; Middle Dutch pote "scion, plant," Dutch poten "to plant," Old Norse pota "to poke."
Obsolete past tense form putted is attested 14c.-15c. From c. 1300 as "to hurl, cast, propel," especially "to throw with an upward and forward motion of the arm" (Will. Putstan is attested as a name from 1296). From mid-14c. in the figurative sense of "bring (someone) into some specified state or condition;" late 14c. as "subject (someone to something)," as in put to death, c. 1400; put to shame, mid-15c. From mid-14c. as "make a declaration, express in speech or writing," hence "express or state (in a particular way)," 1690s, also "propose or place before someone for consideration."
To put (something) back is from 1530s as "to hinder, delay;" 1816 as "restore to the original place or position." To put (something) down "end by force or authority" (a rebellion, etc.) is from mid-14c. To put upon (someone) "play a trick on, impose on" is from 1690s. To put up with "tolerate, accept, bear or suffer without protest or resentment" (1755) is perhaps from put up "to take up" (one's lodgings, etc.), 1727. To put (someone) up in the transitive sense of "lodge and entertain" is by 1766. To put (someone) on "deceive" is from 1958. To put upon (someone) "play a trick on, deceive, impose on" is from 1690s.
1950, from the verbal phrase, "see things on the other side of" (c. 1400); see see (v.) + through (adv.). The verbal phrase see through often is figurative, "perceive the real character of, detect imposture." To see (something) through "continue with until the end" is by 1828 (to see (something) out in the same sense is from 1782).