The story
From New Latin sinus versus (“flipped sine”); the sine function being sometimes called sinus rectus.
Etymology from Wiktionary, CC BY-SA 4.0.
versed sine
Today it means: The trigonometric function 1 − cos(x). Full definition →
Today it means: The trigonometric function 1 − cos(x). Full definition →
From New Latin sinus versus (“flipped sine”); the sine function being sometimes called sinus rectus.
Etymology from Wiktionary, CC BY-SA 4.0.