ˈstēpən, -p ə m verb
( steepened ; steepened ; steepening -p(ə)niŋ ; steepens )
Etymology: steep (I) + -en
transitive verb
: to make steeper : increase
ice sheets of successive glaciations have steepened the valley sides — Samuel Van Valkenburg & Ellsworth Huntington
intransitive verb
: to become steeper
volcanoes have concave slopes that steepen to the summit — Howel Williams
the slant of the line steepened to the vertical — Arthur Mayse