full moon

American  

noun

• full moons
  plural

1. the moon when the whole of its disk is illuminated, occurring when in opposition to the sun.

2. the phase of the moon at this time.

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full moon British  

noun

1. one of the four phases of the moon, occurring when the earth lies between the sun and the moon so that the moon is visible as a fully illuminated disc

2. the moon in this phase

3. the time at which this occurs

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full moon Scientific  

/ fl /

1. The phase of the Moon in which it is visible as a fully illuminated disk. This phase occurs when the Moon is on the opposite side of Earth as the Sun and is not in Earth's shadow.

2. See more at moon Compare new moon

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Other Word Forms

Noun Inflected Forms

• full moons
  plural

Etymology

Origin of full moon

before 1000; Middle English ful moyne, Old English fulles monan

Compare meaning

How does full-moon compare to similar and commonly confused words? Explore the most common comparisons:

• new moon vs. full moon

Example Sentences

See Examples For:

full moon

Saturday's full moon is projected to worsen coastal inundations.

From BBC ● Sep. 26, 2026

A single WFI image will cover an area of sky larger than the apparent size of a full moon.

From Science Daily ● Sep. 21, 2026

Our next full moon, on 26 September, is called the Harvest or Corn Moon as it's the time of year when crops are traditionally gathered.

From BBC ● Aug. 28, 2026

“She was born under a full moon in the arms of mother nature. The jaguars taught her to run, the birds to fly,” her intro video intoned.

From Los Angeles Times ● Apr. 13, 2026

"Anyway," he continued, pointing to the almanac, "to answer your question, the next full moon is tonight."

From "Jeremy Thatcher, Dragon Hatcher" by Bruce Coville