sea slug

American

noun

a nudibranch.

sea slug British

noun

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

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

sea slug Scientific

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

Etymology

Origin of sea slug

First recorded in 1770–80

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

See Examples For:

sea slug

The breakthrough came after he contacted a sea slug expert online.

From Science Daily ● May 27, 2026

Over two decades ago, researchers spotted a mysterious sea slug swimming more than 8,000 feet deep in the Monterey Bay.

From Los Angeles Times ● Nov. 14, 2024

Enrico Somogyi won Compact, with a photo of a nudibranch sea slug with a emperor shrimp on its head, in Tulamben, on the north-east coast of Bali, Indonesia.

From BBC ● Feb. 19, 2024

The blue dragon sea slug steals stinging cells from Portuguese man-of-wars to defend itself.

From National Geographic ● Feb. 7, 2024

And then Roz realized that this type of sea slug was unknown.

From "The Wild Robot Protects" by Peter Brown

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023