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

A known quantity in the insurance world, Shamieh isn’t quite a household name among Berkshire’s many fans and shareholders.

From The Wall Street Journal • May 28, 2026

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

Let us have this as yet very imperfectly known quantity scientifically ascertained, without any attempt either to minimise or to exaggerate.

From The Gospels in the Second Century An Examination of the Critical Part of a Work Entitled 'Supernatural Religion' by Sanday, William