"<a href=""https://www.youtube.com/watch?v=KN2TTiGpDvM&amp;t=1m01s"">1:01</a> This is super nitpicky", but in higher levels of maths, "=" is used for equating, and is closer to most programming languages' "==". However, "≡" is used for defining something, which I would say is closer to assigning than equating,(reply>), No, "≡" is <i>not</i> used to define something. Equivalence is more like "is".<br><br>f(x) = g(x) asks the question "For what x is f(x) the same as g(x)?"<br><br>f(x)≡g(x) tells the reader that g(x) and f(x) are <i>always</i> the same, regardless of what x you choose.