Ambiguous
An ambiguous or poorly defined expression has a definition that does not assign it a unique interpretation or value. An expression which is not ambiguous is said to be well-defined.
See also
Ill-Defined, Well-DefinedExplore with Wolfram|Alpha
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Cite this as:
Weisstein, Eric W. "Ambiguous." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/Ambiguous.html