Sesquiennial
adj
adj ·Rare ·Advanced level
Definitions
Adjective
- 1 Occurring once every one and a half years (i.e. once every 18 months, or twice every three years); sesquiannual. not-comparable
"The endemic Australian sea lion is one of the world's rarest and most unusual seals: rare in terms of very small numbers and unusual in its having a sesquiennial reproductive cycle. [Australian sea lions' breeding cycle is a 17-18 month aseasonal one.]"
Example
More examples"The endemic Australian sea lion is one of the world's rarest and most unusual seals: rare in terms of very small numbers and unusual in its having a sesquiennial reproductive cycle. [Australian sea lions' breeding cycle is a 17-18 month aseasonal one.]"
Etymology
From Latin sesquiennium (compare sesqui- and biennial).
More for "sesquiennial"
Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.