Definition of "slammer"

slammer

noun
plural slammers
1. One who, or that which, slams.
  Quotations
  Margaret was also, by her own admission, a determined slammer of doors.
  1989, Jane Howard, Margaret Mead: A Life, page 27
2. (slang, usually "the slammer") jail, prison.
  Quotations
  A man being sentenced for starving some horses chose 24 hours in the slammer with no food rather than seven days with the regular amenities.
  1971 June 7, “Better Than Prison”, in Time
3. A tequila cocktail that is slammed onto a surface to induce fizzing.
4. One who takes part in slam-dance.
5. One who competes in a poetry slam.
6. In the game of Pogs, the heavier piece used to strike the stack of counters.
  Quotations
  The basic modern 'Pog' game is played thus. Each child tosses a pog into the arena, face-up or face-down, as agreed. Each player in turn takes his slammer and pitches it hard onto the accumulated pile of pogs.
  1997, Iona Archibald Opie, Peter Opie, Children's Games with Things, page 120
7. (UK, slang) A slam-door train.
  Quotations
  I was in Britain, wanting to take a train to Portsmouth, and I only needed a one-way ticket. I did love the English trains; we still had slammers then. A slammer is a train where you got to slam the door shut yourself.
  2009, Claude Lambert, On Pets and Men, page 33