"state of great difficulty or perplexity," 1570s, a word of unknown origin and even the pronunciation is unsettled in old dictionaries (it seems to have been originally accented on the second syllable). Perhaps it is a quasi-Latinism based on Latin quando "when? at what time?; at the time that, inasmuch," pronominal adverb of time, related to qui "who" (from PIE root *kwo-, stem of relative and interrogative pronouns).
"because, inasmuch as, since," used as such from early 16c., originally the present-participle of see (v.).
Then answered the iewes and sayde unto him: what token shewest thou unto us, seynge that thou dost these thynges? [Tyndale, 1526, John ii.18; where Wyclif, 1382, has What token schewist thou to vs, that thou doist these thingis?]
1550s, "of or pertaining to a polity, civil affairs, or government;" from Latin politicus "of citizens or the state" (see politic (adj.)) + -al (1). Meaning "taking sides in party politics" (usually pejorative) is from 1749. Political prisoner first recorded 1860; political science is from 1779 (first attested in Hume). Political animal translates Greek politikon zōon (Aristotle, "Politics," I.ii.9) "an animal intended to live in a city; a social animal":
From these things therefore it is clear that the city-state is a natural growth, and that man is by nature a political animal, and a man that is by nature and not merely by fortune citiless is either low in the scale of humanity or above it ... inasmuch as he is solitary, like an isolated piece at draughts. [Rackham transl.]
c. 1200, piler, "a column or columnar mass, narrow in proportion to height, either weight-bearing or free-standing," from Old French piler "pillar, column, pier" (12c., Modern French pilier) and directly from Medieval Latin pilare, from Latin pila "pillar, stone barrier," a word of unknown etymology. The figurative sense of "prop or support of an institution or community" is recorded from early 14c. Related: Pillared.
In medieval architecture often made so as to give the appearance of several shafts around a central core; "by architects often distinguished from column, inasmuch as it may be of any shape in section, and is not subordinated to the rules of classic architecture" [Century Dictionary].
Phrase pillar to post "from one thing to another without apparent or definite purpose" is attested from c. 1600, late 15c. as post to pillar, mid-15c. as pillar and post; but the exact meaning is obscure. Earliest references seem to allude to tennis, but post and pillar is recorded as the name of a game of some sort c. 1450. The theory that the expression is from pillar as the raised ground at the center of a manège ring around which a horse turns is unlikely because that sense seem to date only to 18c.
The Pillars of Hercules are the two hills on opposite sides of the Straits of Gibraltar, Abyla in Africa and Calpe in Europe, said to have been torn asunder by Hercules.