Stud could refer to any of these :

• stud, a horse or other male animal employed for breeding, or stud farm, an establishment for horse breeding: see horse breeding, animal husbandry, dog breeding, selective breeding
• stud, a male gender role
• ear stud, a form of earring for pierced ears.
• wall stud, a vertical member within a wall frame, usually a two-by-four which reaches from floor to ceiling.
• stud , a fastener, male, with threads.
• Stud poker, a kind of card game
  • Blind stud, game played blind by having all cards dealt face down
  • Five-card stud, a kind of stud poker
  • Seven-card stud, a kind of stud poker
  • Caribbean Stud Poker, a card game similar to Five-card stud