Lambda Nature

Lambda is a greek letter (looks something like an up-side-down back-to-front y) that is often used to represent these things:

An EigenValue of a matrix
The decay constant of a radioactive material (not the half-life), or other exponential process
FunctionalAbstraction? in the LambdaCalculus and, usually spelled out, some programming languages (typically FunctionalProgrammingLanguages, but not always) related to that calculus
In the context of 'lambda sensor', an exhaust oxygen sensor in a closed-loop fuel management system for an internal combustion engine
Wavelength

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.

The cosmological constant
TypeAbstraction? in SystemF

(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!-)