Let $P_X = (X, {\preceq}_X)$ and $P_Y = (Y, {\preceq}_Y)$ each be a D1103: Partially ordered set.
An D427: Isotone map $f : X \to Y$ from $P_X$ to $P_Y$ is an order isomorphism from $P_X$ to $P_Y$ if and only if $f$ is a D468: Bijective map from $X$ to $Y$.