1. Information that is essential to understanding a situation or problem
   - background

Type of: information

• pigeon guillemot
• pigeon hawk
• pigeon loft
• pigeon pea
• pigeon toes
• pigeon-breasted
• pigeon-pea plant
• pigeon-toed
• pigeonhole
• pigeonholing
• pigfish
• piggery
• piggish
• piggishly
• piggishness
• piggy
• piggy bank
• piggyback
• piggyback plant
• pigheaded
• pigheadedness
• piglet
• pigman
• pigment
• sun plant