plural of Fei

(intransitive) To make a clumsy or stupid mistake. / (intransitive) To move blindly or clumsily. / (transitive) To cause to make a mistake.

(mathematics) A notation that denotes a number that is 1 if the condition in square brackets is satisfied, and 0 otherwise, i.e. (where P is a true or false statement)

A primitive mitochondrion that lacks some inner membranes