STEEPEN
Meaning of STEEPEN in English
/ ˈstiːpən; NAmE / verb
to become or to make sth become steeper :
[ v ]
After a mile, the slope steepened.
[also vn ]
Oxford Advanced Learner's English Dictionary.
Оксфордский английский словарь для изучающик язык на продвинутом уровне.
2005