quadriliteral adj.

before vowels quad- (before -p- often quadru-, from an older form in Latin), word-forming element used in compounds of Latin origin and meaning "four, four times, having four, consisting of four," from Latin quadri-, which is related to quattor "four" (from PIE root *kwetwer- "four").

late 14c., "taking words in their natural meaning" (originally in reference to Scripture and opposed to mystical or allegorical), from Late Latin literalis/litteralis "of or belonging to letters or writing," from Latin litera/littera "letter, alphabetic sign; literature, books" (see letter (n.1)). Related: Literalness.

Meaning "of or pertaining to alphabetic letters" is from late 14c. Meaning "concerned with letters and learning, learned, scholarly" is from mid-15c. Sense of "verbally exact, according to the letter of verbal expression" is attested from 1590s, as is application to the primary sense of a word or passage. Literal-minded is attested from 1791.

Proto-Indo-European root meaning "four."

It forms all or part of: cadre; cahier; carillon; carrefour; catty-cornered; diatessaron; escadrille; farthing; firkin; fortnight; forty; four; fourteen; fourth; quadrant; quadraphonic; quadratic; quadri-; quadrilateral; quadriliteral; quadrille; quadriplegia; quadrivium; quadroon; quadru-; quadruped; quadruple; quadruplicate; quarantine; quarrel (n.2) "square-headed bolt for a crossbow;" quarry (n.2) "open place where rocks are excavated;" quart; quarter; quarterback; quartermaster; quarters; quartet; quarto; quaternary; quatrain; quattrocento; quire (n.1) "set of four folded pages for a book;" squad; square; tessellated; tetra-; tetracycline; tetrad; tetragrammaton; tetrameter; tetrarch; trapezium.

It is the hypothetical source of/evidence for its existence is provided by: Sanskrit catvarah, Avestan čathwaro, Persian čatvar, Greek tessares, Latin quattuor, Oscan petora, Old Church Slavonic četyre, Lithuanian keturi, Old Irish cethir, Welsh pedwar.