noun

• (UK, Oxford University slang) One of the proctors' officers.
  "[…] and was confronted by a “bulldog,” a proctor's assistant in charge of discipline, who asked if he was a member of the university since he wasn't wearing a gown, and he was able to say that he wasn't, […]"
• (professional wrestling) Any move in which the wrestler grabs an opponent's head and jumps forward, so that the wrestler lands, often in a sitting position, and drives the opponent's face into the mat.
• (US, publishing) A bulldog edition.
  "The bulldog's just gone to press."
• (chiefly UK, sometimes capitalized) The children's game of British Bulldog or Red Rover.
  ""... playing bulldog in the yard so I know you're fit enough to fight. Have you decided when you're coming back?”"

verb

• (intransitive, often with into or through) To force oneself (in a particular direction).
  "So to give you some idea, we had scenarios where Yamato came steaming over the horizon and just bulldogged its way straight through the American battleline, and the whole thing was done and dusted inside of an hour, with 18-inch shells just blowing apart anything in sight."
• (transitive) To chase (a steer) on horseback and wrestle it to the ground by twisting its horns (as a rodeo performance).