quadri-

Quadri- is a combining form used like a prefix meaning “four.” It is used in a great variety of technical and scientific terms.

Quadri- comes from the Latin quattuor, meaning “four.” The Greek equivalent is tetra-, which also appears as tetr-, as in tetrahedron. Want to know more? Check out our Words That Use entries for tetr- and tetra-.

What are variants of quadri-?

When combined with words or word elements that begin with a vowel, quadri- becomes quadr-, as in quadric.

In other instances, quadri- becomes quadra-, as in quadraphony.

Before some labial consonants (such as –p– or –f-), quadri- becomes quadru-, as in quadruplex, which uses the Latin equivalent of the form.

Want to learn more? Check out our Words That Use entries for quadr-, quadra-, and quadru-.

An example of a word you may have encountered that features quadri- is quadrilateral, “having four sides.” The word comes from Latin quadrilaterus, which uses the equivalent of the form quadri-.

We know quadri- means “four,” and the -lateral portion of the word means “of or relating to the side,” from Latin laterālis. Quadrilateral literally translates to “of or relating to four sides.”

What are some words that use the combining form quadri-?

• quadribasic
• quadriceps (using the equivalent form of quadri- in Latin)
• quadrigeminal
• quadrilingual
• quadrisect
• quadrisyllable

What are some other forms that quadri- may be commonly confused with?

• quasi-
• quinque-

Not every word that begins with the exact letters quadri- is necessarily using the combining form quadri- to denote “four.” Quadrille, although it comes from a related Latin word, is one such word that does not use the form quadri-. Learn what the quadrille dance has to do with the number four at our entry for the word.

The word lingual has various meanings, including “pertaining to languages.” For example, someone who is bilingual speaks two languages. With this in mind, a quadrilingual person speaks how many languages?