Definition of openers:
(n) :
A person who opens something.
(n) :
A device that opens something; specifically a tin-opener/can-opener, or a bottle opener.
(n) :
(in combination) An establishment that opens.
(n) :
(colloquial) The first in a series of events, items etc.; the first remark or sentence of a conversation.
(n) :
(card games) The player who starts the betting.
(n) :
(card games, in the plural) Cards of sufficient value to enable a player to open the betting.