- (arithmetic, logic) A notation for arithmetic (logical) formulae in which operations (respectively, quantifiers and operands) are written immediately before their operands, used to avoid the need for parentheses; for example, 3 * (4 + 7) is written as * 3 + 4 7 and
*A*AND*B*is written as AND*A**B*.

After the nationality of the logician Jan Åukasiewicz