invertebrate

American  

[in-vur-tuh-brit, -brayt] / ɪnˈvɜr tə brɪt, -ˌbreɪt /

adjective

1. Zoology.

   1. not vertebrate; without a backbone.

   2. of or relating to creatures without a backbone.

2. without strength of character.

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noun

• invertebrates
  plural

1. an invertebrate animal.

2. a person who lacks strength of character.

invertebrate British  

/ ɪnˈvɜːtɪbrɪt, -ˌbreɪt /

noun

1. any animal lacking a backbone, including all species not classified as vertebrates

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adjective

1. of, relating to, or designating invertebrates

invertebrate Scientific  

/ ĭn-vûr′tə-brĭt,-brāt′ /

1. Having no backbone or spinal column.

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1. An animal that has no backbone or spinal column and therefore does not belong to the subphylum Vertebrata of the phylum Chordata. Most animals are invertebrates. Corals, insects, worms, jellyfish, starfish, and snails are invertebrates.

Other Word Forms

Derived Forms

• invertebracy
  noun
• invertebrateness
  noun

Inflected Forms

Nouns

• invertebrates
  plural

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Etymology

Origin of invertebrate

From the New Latin word invertebrātus, dating back to 1820–30. See in- ³, vertebrate

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Explanation

An invertebrate is an animal without a backbone. Invertebrate animals include fruit flies and sea sponges. Your backbone allows you to stand up straight, and it also allows you to be grouped with the other vertebrates: animals with backbones. Invertebrates are the opposite: they have no backbone. These are the two major groups of animals. Also, this word is used for people who are spineless in the sense of having no courage. You could say a coward acts in an invertebrate way. Whether it's a backbone-free animal or a courage-free person, all invertebrates lack spines.

Example Sentences

See Examples For:

invertebrate invertebrates

The invertebrate paleontology collections overseen by Drs. Cole and Wright at the Oklahoma Museum of Natural History contain more than a million specimens, and additional fossils are added every year.

From Science Daily ● Aug. 21, 2026

Using a technique called riverfly monitoring, the sampling looks at levels of invertebrate life in the water, which means any pollution or deterioration in water quality can be quickly detected.

From BBC ● Jul. 12, 2026

Researchers say these impacts make it especially important to assess the risks on Mediterranean islands, where many unique invertebrate and vertebrate species are found nowhere else.

From Science Daily ● Jul. 11, 2026

After three years the invertebrate population of that area was still 90% lower.

From BBC ● May 2, 2026

In organic chemistry, invertebrate zoology, and the inspired symmetry of Mendelian genetics, I have found a religion that serves.

From "The Poisonwood Bible" by Barbara Kingsolver

They were the first invertebrates -- a broad group of animals including spiders, snails and worms -- shown to use celestial navigation for such long trips.

From Barron's ● Oct. 2, 2026

The eight years Darwin spent dismembering these tiny invertebrates at home took up more than 20 pages in Ms. Browne’s old version; they now receive barely four.

From The Wall Street Journal ● Oct. 2, 2026

The animals, including marine fish, invertebrates and sharks, arrived at the aquarium on June 19, but the aquarium didn’t announce the news until Thursday.

From Los Angeles Times ● Aug. 28, 2026

Spiders belong to a large group of invertebrates called chelicerates, which also includes scorpions and ticks.

From Science Daily ● Aug. 4, 2026

Offshore, an unfinished break wall was home to kelp beds and invertebrates.

From "The Line Tender" by Kate Allen

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