blue whale

American  

[bloo hweyl, weyl] / ˈblu ˈʰweɪl, ˈweɪl /

noun

1. a migratory baleen whale, Balaenoptera musculus, mostly of oceans and seas in the Southern Hemisphere, the largest mammal ever known, growing to a length of 100 feet (30.5 meters) and having a furrowed, slate-blue skin mottled with lighter spots, in some seas acquiring a yellowish coating of diatoms on the underside: now classified as endangered, it was once hunted nearly to extinction, but international conservation efforts begun in the 1960s have enabled the blue whale population to rebound significantly.

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blue whale British  

noun

1. Also called: sulphur-bottom.  the largest mammal: a widely distributed bluish-grey whalebone whale, Sibbaldus (or Balaenoptera ) musculus , closely related and similar to the rorquals: family Balaenopteridae

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Etymology

Origin of blue whale

First recorded in 1850–55

Example Sentences

Jake, nestled into his sleeping bag on a cot underneath the museum's gigantic suspended model of a blue whale, said he was "so happy to be here."

From Barron's • Oct. 25, 2025

He was shown the rest of the process including a DNA extraction machine that produces the DNA code sequence that allows the team to identify everything from bacteria to a blue whale.

From BBC • Jan. 29, 2025

The blue whale is usually considered the largest creature in the ocean.

From NewsForKids.net • Nov. 27, 2024

These results are consistent with studies of Antarctic blue whale songs, heard throughout the Southern Ocean.

From Science Daily • Nov. 15, 2024

“For Emily Dickinson. Maybe this blue whale is my letter to the world.”

From "Ivy Aberdeen’s Letter to the World" by Ashley Herring Blake