What is the meaning of pet?

noun

• A domesticated animal kept for companionship or amusement.
• A special loved one.
  • synonyms: darling, favorite, favourite, dearie, deary, ducky
• A fit of petulance or sulkiness (especially at what is felt to be a slight. )
• Using a computerized radiographic technique to examine the metabolic activity in various tissues (especially in the brain.
  • synonyms: positron emission tomography

verb

• Stroke or caress gently.
  • usage: "pet the lamb"
• Stroke or caress in an erotic manner, as during lovemaking.

adjective

• Preferred above all others and treated with partiality.
  • usage: "the favored child"
  • synonyms: favored, favorite, favourite, best-loved, preferred, preferent