infinitely or immeasurably small; "two minute whiplike threads of protoplasm"; "reduced to a microscopic scale"
a non zero element smaller in magnitude than any positive real
a number greater than zero yet smaller than any positive real number
a number so small that we cannot distinguish it from zero
Very small quantity, approaching zero.
In mathematics, an infinitesimal, or infinitely small number, is a number that is smaller in absolute value than any positive real number. A number x is an infinitesimal if and only if for every integer n, |nx| is less than 1, no matter how large n is. In that case, 1/x is larger in absolute value than any positive real number.