an First Order ODE is “autonomous” when:
\begin{equation} y’ = f(y) \end{equation}
for some f of one variables. Meaning, it only depends on the independent variable t through the use of y(t) in context. This is a special class of seperable diffequ. autonomous ODEs level off at stationary curves for autonomous ODEs can never level off at non-stationary points. Otherwise, that would be a stationary point. See stability (ODEs) time-invariant expressions For forms by which:
\begin{equation} y’ = f(y) \end{equation}
as in, the expression is time invariant.