diplo-

Diplo- is a combining form used like a prefix meaning “double” or “in pairs.” This form is frequently used in scientific terms, especially in zoology and botany.

Diplo- comes from Greek diplóos, meaning “twofold” or “double-folded.” Distantly related is Latin duplex, which also literally means “twofold.”

What are variants of diplo-?

When combined with words or word elements that begin with a vowel, diplo- becomes dipl-, as in diploid.

One example of a term that features diplo- you may have seen is diplodocus, “a huge herbivorous dinosaur of the genus Diplodocus, growing to a length of about 87 feet.” Diplodocus comes from the New Latin Diplodocus, which uses the equivalent of the form diplo-.

Dippy was revealed to the public #OTD in 1905 and he became an instant star. Hear from the Diplodocus himself as he shares some of his memorable moments from the Museum Archives. https://t.co/rk6niJ0MlM pic.twitter.com/euLY6n220t

— Natural History Museum (@NHM_London) May 12, 2018

As we know, diplo- means “double,” while the -docus part of diplodocus means “beam, bar, shaft,” from Greek dokós. Diplodocus literally translates to “double beams,” a reference to the double row of bones in its tail.

What are some words that use the combining form diplo- or dipl-?

• diplobiont
• diplocardia
• diplogenesis
• diploid
• diplomyelia
• diplophase
• diplophonia (using the equivalent form of diplo- in Latin)

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

• dep.
• di-
• pleo-

Not every word that begins with the letters diplo- is necessarily using the combining form diplo- to mean “double.” Diploma and diplomatic are two such examples. Both of these words, as it happens, ultimately come from the same root as diplo-, but they aren’t using diplo- as a combining form. Learn why diploma is a type of document and why diplomatic means “tactful” at our entry for each word.

In suffix -oid means “resembling, like.” With this in mind, what does diploid mean?