SINCE 1828

An Encyclopædia Britannica Company

arcsine

noun arc·sine \ (ˌ)ärk-ˈsīn \

Definition of arcsine

: the inverse function of the sine

if y is the sine of θ, then θ is the arcsine of y

—abbreviation arcsin

First Known Use of arcsine

circa 1889

in the meaning defined above

See Words from the same year

NEW! Time Traveler

Seen and Heard

What made you want to look up arcsine? Please tell us where you read or heard it (including the quote, if possible).

show

WORD OF THE DAY

slew

play

a large number

Words at Play

alt-5adf93a49b0b2

The Fossil Encased in "Case In Point"

"In point" only lives in this phrase.

alt-5adf5d017e6bf

‘Sleight’ or ‘Slight’ of Hand?

Watch closely and be amazed.

alt-5ade0f1ca7a0c

'Complement' vs. 'Compliment'

The distinction is clear (now).

Words from Letters in the Greek Alphabet

When English borrows from another alphabet

Ask the Editors

2017 Word of the Year: Behind the Scenes

How we chose 'feminism'

video-title-words-of-the-year-1066

Words of the Year: 1066

Or, Why Pig Meat is Called 'Pork' and Cow Meat is Called 'Beef'

video-literally

Literally

How to use a word that (literally) drives some people nuts.

video-his-or-her

Is Singular 'They' a Better Choice?

The awkward case of 'his or her'

Word Games

Odd Habits and Quirks Quiz

Test your knowledge of strange human behaviors.

Take the quiz

cats-on-impossible-timber

More Confusing Words—Quiz

How many of these commonly confused words do you know?

Take the quiz

Name That Thing

Name That Thing

Test your visual vocabulary with our 10-question challenge!

Take the quiz

SCRABBLE® Sprint

SCRABBLE® Sprint

SCRABBLE® fans, sharpen your skills!

Play the game