laterigrade

American  

[lat-er-i-greyd] / ˈlæt ər ɪˌgreɪd /

adjective

1. having a sideways manner of moving, as a crab.

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laterigrade British  

/ ˈlætərɪˌɡreɪd /

adjective

1. zoology (of some crabs) having a gait characterized by sideways movement

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Etymology

Origin of laterigrade

First recorded in 1750–60; < Latin later- (stem of latus “side, flank”) + -i- ( def. ) + -grade

Explanation

Crabs are known for their laterigrade, or sideways, movement. While most animals move forward or backward, a laterigrade animal's body is designed to move left or right. It's not just crabs that move sideways; some spiders do, too, especially those called "crab spiders." Laterigrade creatures have legs that extend outward from the body, allowing them to move sideways, sometimes at great speed. This sideways movement helps the creatures squeeze into narrow crevices or ambush prey from unexpected angles. The word laterigrade comes from the Latin roots lateris, meaning "side," and gradus, meaning "step."