Definitions
from The American Heritage® Dictionary of the English Language, 4th Edition
 n. An algebraic quantity that when raised to a certain power equals zero.
from Wiktionary, Creative Commons Attribution/ShareAlike License
 adj. Describing an element, of a ring, for which there exists some positive integer n such that xn = 0.
from The Century Dictionary and Cyclopedia
 In mathematics, vanishing on being raised to a certain power. Thus, if i be such an expression in multiple algebra that i × i × i = 0, i is nilpotent
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
 adj. equal to zero when raised to a certain power
Etymologies
from The American Heritage® Dictionary of the English Language, 4th Edition
Examples

There is nothing inconsistent with this restriction, and the positive L_m in isolation generate a gauge symmetry; there is no anomaly in the positive sector and thus a nilpotent BRST operator.

Hence this subalgebra admits a nilpotent BRST operator, and can be viewed as a gauge symmetry.

The BRST operator for the full Virasoro algebra is not nilpotent, and hence a global symmetry.

Multi function printer say, as a thyrotropin, she may be nilpotent or cislunar and may act plumb in plagiarized.

One application of the solvable Freiman theorem is the following quantitative version of a classical result of Wolf, which asserts that any solvable group of polynomial growth is virtually nilpotent:

x (for m ¥ 2) which George Boole had introduced in this form in his algebra of logic in 1847; and ˜nilpotent™, when xm = 0, for some m.

It provides a rigorous framework for mathematical analysis in which every function between spaces is smooth (i.e., differentiable arbitrarily many times, and so in particular continuous) and in which the use of limits in defining the basic notions of the calculus is replaced by nilpotent infinitesimals, that is, of quantities so small (but not actually zero) that some power ” most usefully, the square ” vanishes.
deinonychus commented on the word nilpotent
I have a feeling that it could work well as an insult of some sort...
April 2, 2014
ruzuzu commented on the word nilpotent
"In mathematics, vanishing on being raised to a certain power. Thus, if i be such an expression in multiple algebra that i × i × i = 0, i is nilpotent."  Century
April 2, 2014