What is a lambda (function)?

Question

For a person without a comp-sci background, what is a lambda in the world of Computer Science?

Answer 1

The question is formally answered greatly, so I will not try to add more on this.

In very simple, informal words to someone that knows very little or nothing on math or programming, I would explain it as a small "machine" or "box" that takes some input, makes some work and produces some output, has no particular name, but we know where it is and by just this knowledge, we use it.

Practically speaking, for a person that knows what a function is, I would tell them that it is a function that has no name, usually put to a point in memory that can be used just by referencing to that memory (usually via the usage of a variable - if they have heard about the concept of the function pointers, I would use them as a similar concept) - this answer covers the pretty basics (no mention of closures etc) but one can get the point easily.