A parenthesis-free notation for forming mathematical expressions in which each operator precedes its operands WordNet 3.0 & Open English WordNet

Polish notation, also known as normal Polish notation, Łukasiewicz notation, Warsaw notation, Polish prefix notation or simply prefix notation, is a mathematical notation in which operators precede their operands, in contrast to the more common infix notation, in which operators are placed between operands, as well as reverse Polish notation, in which operators follow their operands. Wikipedia

A prefix notation proposed by Jan Łukasiewicz Wikipedia Disambiguation

Mathematical notation in which every operator precedes all of its operands Wikidata

A notation for arithmetic (and 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. Wiktionary

Notation for arithmetic formulae. Wiktionary (translation)