noun

• (programming) A variable, memory location, etc. whose contents are incremented to keep a count.
  "With a foreach block, you don't need to create an explicit counter variable."
• (Internet) A hit counter.
• (curling) Any stone lying closer to the center than any of the opponent's stones.
• (historical) The prison attached to a city court; a compter.
  "He remaynes prisonner in the Counter in Woodstrete in the hole, by the contagiousing wherof he is lyke to perishe"

noun

• (martial arts) A proactive defensive hold or move in reaction to a hold or move by one's opponent.
  "Always know a counter to any hold you try against your opponent."
• (nautical) The overhanging stern of a vessel above the waterline, below and somewhat forward of the stern proper.
• (music) Alternative form of contra Formerly used to designate any under part which served for contrast to a principal part, but now used as equivalent to countertenor.
• (typography) The enclosed or partly closed negative space of a glyph.

verb

• (boxing) To return a blow while receiving one, as in boxing.
  "His left hand countered provokingly."
• (transitive, obsolete) To encounter.