From WordNet (r) 3.0 (2006) :
prefix notation
n 1: a parenthesis-free notation for forming mathematical
expressions in which each operator precedes its operands
[syn: prefix notation, Lukasiewicz notation, Polish
notation]
From The Free On-line Dictionary of Computing (30 December 2018) :
prefix notation
prefix syntax
(Or "prefix syntax") One of the possible orderings
of functions and operands: in prefix notation the function
precedes all its operands. For example, what may normally be
written as "1+2" becomes "(+ 1 2)". A few languages (e.g.,
lisp) have strictly prefix syntax, many more employ prefix
notation in combination with infix notation.
The opposite, postfix notation, is somewhat rarer.
(2014-07-08)