Lambda is a greek letter (looks something like an up-side-down back-to-front y) that is often used to represent these things:
These are represented by lower case lambda (λ or λ).
By talking about the lambda nature of a programming language, we usually mean the tendency of treating functions as values (instead of special constructs) and functions having LexicalClosures.
There is also a capital Lambda (Λ or Λ) -- not sure what that is used for, outside of fraternity house names.
(note: I just tried to type lambdas in Unicode, but somehow they got converted to numeric entity names, which were already there, so I removed them. I'm using Mozilla 1.5.)
try change \frac to \lambda at http://www.equationsheet.com/entertex.php?SID=XXXXXBOT''
Does a dog have lambda nature? MuAnswer.
No no, mu is the next Greek letter!-)
See also MathematicalNotation