Synapsid

//sɪˈnapsɪd// adj, noun

adj, noun ·Rare ·Advanced level

Definitions

Noun
  1. 1
    Any animal (all mammals) of the class Synapsida.
  2. 2
    extinct reptile having a single pair of lateral temporal openings in the skull wordnet
Adjective
  1. 1
    Pertaining to the class Synapsida, of animals which have an opening low in the skull roof behind each eye, leaving a bony arch beneath each. not-comparable

    "We are synapsid tetrapods, a group of reptiles that almost went extinct 200 million years ago in competition with the better-designed dinosaurs."

Synonyms

All synonyms
mammal-like reptilestem mammalsynapsid reptile

Example

More examples

"We are synapsid tetrapods, a group of reptiles that almost went extinct 200 million years ago in competition with the better-designed dinosaurs."

Etymology

From translingual Synapsida, from syn- + Ancient Greek ἁψίς (hapsís, “arch”).

More for "synapsid"

SynonymsSentencesPronunciationTranslate

Next best steps

Find stronger synonymsSee usage examplesCheck pronunciationBrowse writing guides

Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.