opener

noun

1. A person who opens something.

   “Have you, like the opener of this debate, discovered, sapiently enough, that "the peace party, with Lord Aberdeen at their head, were the chief cause of the war"?”

2. A device that opens something; specifically a tin-opener/can-opener, or a bottle opener.
3. (in-compounds)An establishment that opens.

   “The late-night openers in the mall include two restaurants and a clothing store.”

4. The player who starts the betting.
5. (in-plural)Cards of sufficient value to enable a player to open the betting.
6. A person employed to separate sheets of hot metal that become stuck together.
7. The first act in a variety show or concert.
8. A batsman or bowler who normally plays in the first two positions of an innings.
9. (colloquial)The first in a series of events, items etc.; the first remark or sentence of a conversation.
10. The first game played in a competition.

    “The opener came from a Jarvis ball which struck Aleksandar Kolarov en route to a lively round of pinball between City players before it was poked in by Milijas.”

    “England were on the scoreboard after only one minute, Wilkinson, who missed five penalties in his side's opener against the Pumas, knocking over a three-pointer from bang in front, despite boos from the crowd.”

    “His debut was highly anticipated, but Rodgers only saw 94 seconds of game time as he suffered the significant injury in the Jets’ season opener against the Buffalo Bills when he was sacked by edge rusher Leonard Floyd, only four plays in.”

11. A opening goal.
12. A period of time when it is legal to commercially fish.
13. A pitcher who specializes in getting the first outs of a game before being replaced, either by a long reliever or a pitcher who would normally start.

    “The Rays debuted the opener—in which a reliever starts the game and throws anywhere from one to three innings, then gives way to a new pitcher, who will usually throw three to five as essentially a second starter—on May 19 against the Angels, using veteran righty Sergio Romo to pitch the first.”

adj

1. (comparative, form-of)comparative form of open: more open

   “The letter y is also used for the slightly opener non-fricative sound heard in English year.”

   “Lower-middle-class speakers in New York showed a strong tendency to report themselves as using [æː] in the word pass, although as objectively observed they tended to use the pronunciation with [ɛːə]. And in the most formal style (word lists) they produced on average an opener quality than the upper-middle-class speakers – an example of Labov-hypercorrection.”