I might as well get a reaction on these idle thoughts or I will continue to think them. Something must be left over from schoolroom or uni because it seems to me a number mathematical terms have been incorporated into everyday or colloquial language. One that I think is relatively recent is 'factor out'. It is used in close to mathematical meaning, you have a problem about F but F = f X g, so you can factor out f and worry just about g. The best other example I can think of is 'a function of'. Others are in terms of, lowest common denominator occasionally l.c. factor , exponentially. We have to consider whether any example is really an example. An infinite number of examples maybe did not come from maths? Nor maybe go off on a tangent? - though that always makes me picture a circle with a tangent line and a point moving round the circle but when it meets the tangent goes along that. Of most interest are fairly widespread ones, not very slangy or confined to a small circle, e.g. students, at least let us distinguish them (general solutions more than special cases?) and talk about where we think they came from. Though maybe colloquial things do start in small circles - I have an impression that 'factor out' which I cannot remember in use ten or twenty years ago started with people who need to sound streetsmart, financial advisors, estate agents,... I cannot resist quoting one which I read is confined to Philadelphia - factorial. As in "She's size 12" "No man, she's size factorial 12!". Quite witty! No doubt there will be some transatlantic differences. Any thoughts or other examples?