known quantity

American  

noun

1. Mathematics. a quantity whose value is given: in algebra, frequently represented by a letter from the first part of the alphabet, as a, b, or c.

2. any factor, circumstance, etc., that is already accepted or familiar.

   Her honesty is a known quantity.

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Etymology

Origin of known quantity

First recorded in 1975–80

Example Sentences

Todd Blanche is a known quantity in Trump World.

From Salon • Apr. 22, 2026

As such, Warsh is a known quantity in upper-echelon social, political, and economic circles.

From Barron's • Feb. 2, 2026

Now a known quantity, Saints reduced their kicking to Caluori to deal with the breakout star's freakish aerial ability, while the teenager struggled to get the ball in hand to show his running power.

From BBC • Oct. 27, 2025

He is, in other words, a known quantity.

From Slate • Jan. 9, 2025

The sturdy big stretch-runner from the Curry barn had not been defeated at the meeting; he was the known quantity and could be depended upon to run his usual honest race.

From Old Man Curry Race Track Stories by Van Loan, Charles E. (Charles Emmett)