noun

• An adult male of domesticated cattle or oxen.
• (finance) An investor who buys (commodities or securities) in anticipation of a rise in prices.
  "This accompt has been made to appear a bull accompt, i.e. that the bulls cannot take their stock. The fact is the reverse; it is a bear accompt, but the bears, unable to deliver their stock, have conjointly banged the market, and pocketed the tickets, to defeat the rise and loss that would have ensued to them by their buying on a rising price on the accompt day […]"
• (US, slang) A policeman; a detective; a railroad security guard.
  "You never waited until the train stopped to get off. The railroad bulls were waiting at the stops searching for freeloaders."
• (LGBTQ, slang) An elderly lesbian.

adj

• (attributive, of large mammals) Adult male.
  "a bull elephant"
• (finance) Characterized by rising prices or belief that prices will rise.
  "a bull market"

verb

• (intransitive, often with into or through) To force oneself (in a particular direction); to move aggressively.
  "He bulled his way in."
• (agriculture, intransitive, of a cow or heifer) To be in heat; to be ready for mating with a bull.
• (agriculture, transitive, of a bull) To mate with (a cow or heifer).
• (finance, transitive) To endeavour to raise the market price of.
  "to bull railroad bonds"

verb

• (dated) To publish in a papal bull.