pentangle n.

word-forming element in words of Greek origin or formation meaning "five, containing five," from Greek penta- (before a vowel pent-), combining form of pente "five," related to Aeolian pempte (from PIE root *penkwe- "five"), with -a- probably by analogy of hepta-, ennea-, deka-.

"space or difference in direction between intersecting lines," late 14c., from Old French angle "an angle, a corner" (12c.) and directly from Latin angulus "an angle, a corner," a diminutive form from PIE root *ang-/*ank- "to bend" (source also of Greek ankylos "bent, crooked," Latin ang(u)ere "to compress in a bend, fold, strangle;" Old Church Slavonic aglu "corner;" Lithuanian anka "loop;" Sanskrit ankah "hook, bent," angam "limb;" Old English ancleo "ankle;" Old High German ango "hook").

The figurative sense "point or direction from which one approaches something" is from 1872. Angle-bracket is attested by 1781 in carpentry; 1956 in typography.

1590s, "mathematical figure (presumably originally one of five points) used in magical ceremonies and considered a defense against demons," from Medieval Latin pentaculum "pentagram," a hybrid coined from Greek pente "five" (from PIE root *penkwe- "five") + Latin -culum, diminutive (or instrumental) suffix. OED notes other similar words: Italian had pentacolo "anything with five points," and French pentacle (16c.) was the name of something used in necromancy, perhaps a five-branched candlestick; French had pentacol "amulet worn around the neck" (14c.), from pend- "to hang" + a "to" + col "neck." The same figure as a pentagram, except in magical usage, where it has been extended to other symbols of power, including a six-point star. Related: Pentacular.