prot-

Prot– is a combining form used like a prefix meaning “first,” “foremost,” or “earliest form of.” In terms from chemistry, it specifically denotes either the first in a series of compounds or the compound containing the minimum amount of an element. It is often used in scientific and technical terms, especially in biology.

Proto– comes from Greek prôtos, meaning “first.” The word proton, meaning “a positively charged elementary particle,” ultimately shares this same Greek root. The Latin cognate of prôtos is prīmus “first,” which is the source of primary and prime. Check out our entries for both words to learn more.

What are variants of prot-?

Prot– is a variant of proto–, which loses its –o– when combined with words or word elements beginning with vowels. Want to know more? Read our Words That Use proto– article.

One example of a word you may have encountered that features the form prot– is protagonist, “the leading character, hero, or heroine of a drama or other literary work.” The word protagonist comes from Greek prōtagōnistḗs, which features the equivalent of prot– in that language.

The form prot– means “first” or “foremost” as we know, but what about –agonist? The ending –agonist comes from Greek agōnistḗs, meaning “one who contends for a prize, combatant, actor.” Protagonist literally translates to “foremost actor.”

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

• protamine
• protandrous
• protanopia (using the equivalent form of prot– in Latin)
• protist (using the equivalent form of prot– in Greek)
• protium

What are some other forms that prot– may be commonly confused with?

• pro-
• proct-
• procto-
• prote-
• protero-

Not every word that begins with the exact letters prot-, such as Proteus or protean, is necessarily using the combining form prot– to denote “first.” Learn why protean means “extremely variable” at our entry for the word.

The form -androus means “male.” With this in mind, what does protandrous literally mean?