tetrapod
/ˈtɛtrəpɑd/
noun
- A four-legged animal, especially a vertebrate (such as an amphibian, reptile, bird, or mammal) that has or evolved from ancestors with four limbs.
- The first tetrapods crawled out of the water onto land millions of years ago.
- Frogs are tetrapods, even though they lose their tails as adults.
- Birds are tetrapods because they evolved from four-legged reptiles.
- A concrete or stone structure with four projecting arms, used as a breakwater or to protect shorelines from erosion.
- The harbor was protected by a row of massive tetrapods that broke the waves.
- Each tetrapod weighed several tons and was carefully lowered into place by a crane.
- Engineers placed tetrapods along the coast to prevent beach erosion.
Synonyms