mosasaur

American  

[moh-suh-sawr] / ˈmoʊ səˌsɔr /

noun

1. any of several extinct carnivorous marine lizards from the Cretaceous Period, having the limbs modified into broad, webbed paddles.

---

mosasaur British  

/ ˌməʊsəˈsɔːrəs, ˈməʊsəˌsɔː /

noun

1. any of various extinct Cretaceous giant marine lizards of the genus Mosasaurus and related genera, typically having paddle-like limbs

---

mosasaur Scientific  

/ mō′sə-sôr′ /

1. Any of various medium-sized to large extinct aquatic lizards of the family Mosasauridae of the Cretaceous Period, having modified limbs that served as paddles for swimming. Some species reached lengths of over 15 meters (50 feet).

---

Etymology

Origin of mosasaur

< New Latin Mosasaurus (1823) genus name, equivalent to Latin Mosa the Meuse river (where a species was first discovered) + New Latin -saurus -saur

Example Sentences

Scientists have identified a massive new species of mosasaur, a marine reptile that lived alongside the dinosaurs and dominated prehistoric oceans.

From Science Daily • May 23, 2026

Earlier discoveries of mosasaur bones at a nearby site support this estimate.

From Science Daily • Dec. 15, 2025

To solve this puzzle, researchers from the United States, Sweden, and the Netherlands examined the chemical makeup of the mosasaur tooth enamel using isotope analysis.

From Science Daily • Dec. 15, 2025

Skeletal replicas of the terrifying mosasaur, a Komodo Dragon relative with a six-foot jaw; the saber-toothed salmon; and other extinct species greet visitors in the museum’s entrance hall.

From The Wall Street Journal • Apr. 2, 2025

And the mosasaurus—that was the biggest, meanest, toothiest, most unstoppable mosasaur there was.

From "Dactyl Hill Squad" by Daniel José Older