(often + against/over) to gain a victory or the ascendancy through strength or superiority; to triumph
(+ on/upon/with) to persuade somebody successfully
She finally prevailed on him to sing
to be frequent; to predominate
The west winds that prevail in the mountains
to be or continue in use or fashion; to persist
a custom that still prevails
[Middle English prevailen from Latin praevalēre, from prae- + valēre to be strong]