locust

American  

[loh-kuhst] / ˈloʊ kəst /

noun

1. Also called acridid, short-horned grasshopper.  any of several grasshoppers of the family Acrididae, having short antennae and commonly migrating in swarms that strip the vegetation from large areas.

2. any of various cicadas, as the seventeen-year locust.

3. any of several North American trees belonging to the genus Robinia, of the legume family, especially R. pseudoacacia, having pinnate leaves and clusters of fragrant white flowers.

4. the durable wood of this tree.

5. any of various other trees, as the carob and the honey locust.

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locust British  

/ ˈləʊkəst /

noun

1. any of numerous orthopterous insects of the genera Locusta, Melanoplus, etc, such as L. migratoria, of warm and tropical regions of the Old World, which travel in vast swarms, stripping large areas of vegetation See also grasshopper Compare seventeen-year locust

2. Also called: locust tree.   false acacia.  a North American leguminous tree, Robinia pseudoacacia, having prickly branches, hanging clusters of white fragrant flowers, and reddish-brown seed pods

3. the yellowish durable wood of this tree

4. any of several similar trees, such as the honey locust and carob

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Other Word Forms

• locust-like adjective
• locustlike adjective

Etymology

Origin of locust

1150–1200; Middle English < Latin locusta grasshopper

Explanation

A locust is a type of grasshopper that goes through a phase of its life when it joins an enormous group of locusts. A swarm of locusts can devastate farm crops and affect food supplies. Locusts aren't a separate species from grasshoppers — instead, locust is what scientists rename a grasshopper that's changed its habitat and behavior dramatically. Locusts arise from specific environmental conditions, usually drought followed by fast plant growth. Normally solitary grasshoppers become gregarious, banding together, and even changing their size and color. Swarms of locusts can fly long distances, landing en masse to devour vegetation. The Latin root of locust, locusta, also means "lobster."

Example Sentences

What’s also true is that 21st century markets can be affected by speculators’ attention, much as wheat crops can be affected by the attention of locust swarms.

From The Wall Street Journal • Apr. 3, 2026

For many people, locust swarms evoke images of ancient plagues, but the danger is very real today.

From Science Daily • Jan. 24, 2026

Crops grown in nutrient-poor soil tend to encourage locust outbreaks because those plants contain high levels of carbohydrates and very little protein.

From Science Daily • Jan. 24, 2026

I also love locust blooms, but I know of only one house near me that has locust trees.

From Los Angeles Times • Feb. 6, 2025

Each plate had a pile of soaked and stewed honey locust beans—mixed with hickory nuts.

From "My Side of the Mountain" by Jean Craighead George

Related Words

• grasshopper