pentagram n.

Proto-Indo-European root meaning "five."

It forms all or part of: cinquain; cinque; cinquecento; cinquefoil; fifteen; fifth; fifty; fin (n.) "five-dollar bill;" finger; fist; five; foist; keno; parcheesi; penta-; pentacle; pentad; Pentateuch; Pentecost; pentagon; pentagram; pentameter; pentathlon; Pentothal; Pompeii; Punjab; punch (n.2) "type of mixed drink;" quinary; quincunx; quinella; quinque-; quinquennial; quint; quintain; quintet; quintile; quintessence; quintillion; quintuple.

It is the hypothetical source of/evidence for its existence is provided by: Sanskrit panca, Greek pente, Latin quinque, Old Church Slavonic pęti, Lithuanian penki, Old Welsh pimp, Old English fif, Dutch vijf, Old High German funf.

noun word-forming element, "that which is written or marked," from Greek gramma "that which is drawn; a picture, a drawing; that which is written, a character, an alphabet letter, written letter, piece of writing;" in plural, "letters," also "papers, documents of any kind," also "learning," from stem of graphein "to draw or write" (see -graphy). Some words with it are from Greek compounds, others are modern formations. Alternative -gramme is a French form.

From telegram (1850s) the element was abstracted by 1959 in candygram, a proprietary name in U.S., and thereafter put to wide use as a second element in forming new commercial words, such as Gorillagram (1979), stripagram (1981), and, ultimately, Instagram (2010). The construction violates Greek grammar, as an adverb could not properly form part of a compound noun. An earlier instance was the World War II armed services slang latrinogram "latrine rumor, barracks gossip" (1944).

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.