In [[APL syntax]], a '''dyadic operator''' is an [[operator]] which takes two [[operand]]s, one on each side. In [[APL\360]] the only dyadic operator was [[Inner Product]], but other operators such as [[Power (operator)|Power]] and [[Compose]] have become common, and languages such as [[J]], [[NARS2000]], and [[dzaima/APL]] have added many experimental dyadic operators.
The term "dyadic operator" refers to the [[operator valence|valence]] of the operator itself, that is, the number of operands. When applied, it produces a [[derived function]], which can have a different [[function valence]]. For example, the [[Inner Product]] is usually a dyadic operator that produces a [[dyadic function]] (<source lang=apl inline>+.× A</source> is a [[SYNTAX ERROR]], unless it's defined to be the [[Determinant]] operator), while [[Power (operator)|Power]] generally produces an [[ambivalent]] function. The [[Compose]] function can produce an ambivalent function <source lang=apl inline>f∘g</source>, or a monadic function <source lang=apl inline>A∘f</source> if an array <source lang=apl inline>A</source> is [[Bind|bound]] to a function <source lang=apl inline>f</source>.