The state or condition of being fixed; Fixation.
{{quote-book|en|year=1995|author=Andreu Mas-Colell|author2=Michael D. Whinston|author3=Jerry R. Green|title=Microeconomic Theory|publisher=Oxford University Press|page=557
Something fixed.
The position of an operator relative to its operand (prefix, postfix) or operands (infix).
(ux)