In Reply to: Unknown entity/quantity posted by Catherine Scottow on October 13, 2008 at 08:04:
: Firstly, what an amazing website! Congratulations.
: I would like to know where the saying "an unknown entity/quantity" comes from. What is the original saying? I have always believed it to be "entity", but most people use "quantity" now.
It's "quantity"; it's a metaphor from mathematics. When working out a sum or an equation, the variables whose value you know are "known quantities". Any whose value you don't know, and have to refer to as "X" or "Y", are "unknown quantities".