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variant of nocti- before a vowel.
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Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2022


What does noct- mean?

Noct- is a combining form used like a prefix meaning “night.” It is occasionally used in scientific terms.

Noct- comes from the Latin nox, meaning “night.” The term nocturnal, meaning “of or related to the night,” also comes from this Latin root. In fact, English’s own word night is ultimately related to the Latin nox.

Also ultimately related to nox is the Greek for “night,” nýx, source of the combining forms nycto- and nyct-, which you can learn about at our Words That Use articles for the forms.

Noct- is a variant of nocti-, which loses its -i– when combined with words or word elements beginning with vowels.

Want to know more? Read our Words That Use nocti- article.

Examples of noct-

One example of a term you may have come across that features the form noct- is noctambulism, also known as somnambulism: it’s “sleepwalking.”

The first portion of the word, noct-, means “night.” The second part of the word, -ambulism, refers to “walking,” from the Latin ambulāre, “to walk.” So, noctambulism literally means “walking at night.”

What are some words that use or are related to the combining form noct-?

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

Break it down!

The combining form uria can indicate a urinary condition. With this in mind, what does the medical condition of nocturia involve?

Medical definitions for noct-


The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.