In the above figure, the side labeled $b$ is the hypotenuse.
The word hypotenuse derives from the Ancient Greek ὑποτείνουσα (hypoteínousa), which means sustaining.
This is the active participle of ὑποτείνω (hypoteínō), which means to subtend or to stretch under.
The word has no applications apart from this specific definition in mathematics.
- 1986: David Wells: Curious and Interesting Numbers ... (previous) ... (next): Glossary
- 1997: David Wells: Curious and Interesting Numbers (2nd ed.) ... (previous) ... (next): Glossary
- 2008: Ian Stewart: Taming the Infinite ... (previous) ... (next): Chapter $5$: Eternal Triangles: The origins of trigonometry