steady state noun

1. A state or condition of dynamic equilibrium with entropy at its maximum (physics)
2. Any oscillation system that continues unchanged indefinitely (telecommunications)

steady-state theory noun (astronomy)

In cosmology, a theory that asserts the universe is in a steady state, being infinitely old and containing the same density of matter at all points and all times, with new matter being created to compensate for the space left by the observed expansion of the universe (cf Big Bang theory under bang¹; also called continuous creation)

go steady (informal)

(esp of a boy and girl not yet engaged to be married) to have a steady relationship, to go about regularly together

steady on!

1. Keep calm!
2. Don't be so foolish, hasty, etc