Definition of red ball:
(n) :
Used other than figuratively or idiomatically: see red, ball.
(n) :
(cricket, journalism, metonymic, uncountable) First-class cricket, as distinct from limited overs cricket (or "white ball". Mainly used to play tests.
(n) :
(law enforcement, slang, US) A high-profile high-priority case which draws political or media attention.
(adj) :
(rail transport) Of or related to priority freight or the trains that carry it.