sea slug

American  

noun

1. a nudibranch.

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sea slug British  

noun

1. any of various shell-less marine gastropod molluscs, esp those of the order Nudibranchia See nudibranch

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sea slug Scientific  

1. Any of various colorful marine gastropods of the suborder Nudibranchia, lacking a shell and gills but having fringelike projections that serve as respiratory organs.

2. Also called nudibranch

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Etymology

Origin of sea slug

First recorded in 1770–80

Example Sentences

A tiny new species of sea slug, smaller than a grain of rice, has been discovered off the coast of Keelung in northern Taiwan.

From Science Daily • May 27, 2026

According to the team, he "never realized Thecacera sesama was a new species until he consulted the sea slug expert 'Hsini Lin teacher' on Facebook."

From Science Daily • May 27, 2026

Over the past 20 years, the team has used the institute’s underwater technology to gather more information on the sea slug.

From Los Angeles Times • Nov. 14, 2024

A nature enthusiast and her father have made a colourful discovery of a sea slug usually found in the Mediterranean in a rock pool in south Devon, a wildlife trust says.

From BBC • Aug. 13, 2024

He pecks for a moment at the scarecrow’s pole that rises in the center of the whirlpool eye, dislodging a tiny phosphorescent sea slug and devouring it.

From "Challenger Deep" by Neal Shusterman