quadri-, quadra-, quad-, quadru-

(Latin: four, fourth; a word element for number 4)

quadriplegia
quadriplegic
quadrireme
quadrisect
quadrisyllable (noun), quadrisyllables (pl)
A word comprised of four units of language larger than a phoneme: The term "dictionary" is a quadrisyllable, because it has four syllables altogether!
quadrivalence
quadrivalent
quadrivalvular
quadrivirate
A union of four men.
quadrivium
Four ways [roads].

The collective name given by the schoolmen (educators) of the Middle Ages to the four "liberal arts"; viz., arithmetic, music, geography, and astronomy.

The quadrivium was the "fourfold way" to knowledge; the trivium, to the "threefold way" to eloquence; both together compiled the Seven Liberal Arts enumerated in the following hexameter: Lingua, Tropus, Ratio, Numerus, Tonus, Angulus, Astra; or the higher division of the seven liberal arts in the Middle Ages, comprising geometry, astronomy, arithmetic, and music .

quadroon
quadrumane
quadrumanous (adjective), more quadrumanous, most quadrumanous
Four-handed or having all four feet adapted for use as hands: The quadrumanous primates; such as, apes and monkeys, have four grasping appendages which they use for climbing, to pick fruit apart, and other manipulative activities.
An ape is showing how it uses both hands and feet as hands.
—This ape was compiled from a section in Google images
that shows it using its hands, and its feet as as if they are hands;
in other words, manipulating with four or quadrumanous appendages.
quadrumvir, quadrumvirate
One of four men.
quadrumvirate

Cross references of word families that are related, partially or totally, to: "four, fourth": quatr-; tessara-; tetra-.