Origin and history of tattoo

[stopper] Middle English tappe "faucet through which liquid can be drawn, hollow or tubular plug for controlling the flow of liquid from a vent or hole," from Old English tæppa, from Proto-Germanic *tappon (source also of Middle Dutch tappe, Dutch tap, Old High German zapfo, German Zapfe). Boutkan gives it no IE etymology.

Perhaps originally a tapering cylindrical peg for a cask, then a hollowed one to draw from it; compare the sense evolution of spigot.

The phrase on tap "ready for use, ready to be drawn and served" is recorded from late 15c. Tap-wrench, used in turning the tool that drives a tap, is attested from 1815.

Old English to, ta, te, "in the direction of, as far as (a place, state, goal)," opposite of from; also "for the purpose of, furthermore;" from West Germanic *to (source also of Old Saxon and Old Frisian to, Dutch toe, Old High German zuo, German zu "to"). Not found in Scandinavian, where the equivalent of till (prep.) is used.

This is reconstructed to be from PIE pronominal base *do- "to, toward, upward" (source also of Latin donec "as long as," Old Church Slavonic do "as far as, to," Greek suffix -dē "to, toward," Old Irish do, Lithuanian da-), from demonstrative *de-. Also see too.

English to also supplies the place of the dative in other languages. The near-universal use of to as the verbal particle with infinitives (to sleep, to dream, etc.) arose in Middle English out of the Old English dative use of to and helped shade out the Old English inflectional endings. In this use to is a mere sign, without meaning. Compare similar use of German zu, French à, de.

As an adverb of motion, direction, etc., "to a place in view, to a thing to be done," in Old English. This use was frequent in Middle English in verbal combinations where it renders Latin ad-, com-, con-, ex-, in-, ob-. As a conjunction, "until, up to the time that," by late Old English.

The distribution of verbs among at, to, with, of has been idiosyncratic and varied. Before vowels it was sometimes shortened to t'. The phrase what's it to you "how does that concern you?" (1819) is a modern form of an old question:

Huæd is ðec ðæs?

[John xxi:22, in Lindisfarne Gospel, c.950]

Used absolutely at the end of a clause. with ellipsis of infinitive (same as the proceeding clause: would do it but don't have time to), it is attested from 14c.; OED reports it "rare before 19th c.; now a frequent colloquialism."