First recorded around 1400–50.
Comes from the late Middle English word ferdkyn or firdekyn.
This is formed from a variant of ferthe, meaning "fourth," and the diminutive suffix -kin.
Sign up for more Word of the Day!

EXAMPLES OF FIRKIN

The antique store had a collection of quaint firkins on display, each with its own unique design.
After the harvest festival, the townspeople gathered around to share stories over slices of bread from a firkin of butter.

It's National Poetry Month, and we’ve created a challenge that really is for everyone. Today’s the last day to submit!

Did you mean cosine?