Symbol for "less than or greater than" (in a partial order)

Question

Is there a common notation for expressing "comparability", viz. the symmetric closure $\leq \cup \geq$, where $\leq$ is a partial order?

Answer 1

My current preferred notation is $\gtreqless$.

@eepperly also pointed out that $\perp$ is common, but that seems somewhat overloaded (usually meaning falsum or more generally the bottom element of a lattice).