Pronunciation: (in"fin-i-tes'u-mul), [key]
1. indefinitely or exceedingly small; minute: infinitesimal vessels in the circulatory system.
2. immeasurably small; less than an assignable quantity: to an infinitesimal degree.
3. of, pertaining to, or involving infinitesimals.
1. an infinitesimal quantity.
2. Math.a variable having zero as a limit.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.