1. Involving four parties
   - quadripartite

See also: many-sided, multilateral

• Western diamondback rattlesnake
• Western Empire
• Western European Summer Time
• western fence lizard
• western gray squirrel
• western grey squirrel
• western hemisphere
• western hemlock
• western holly fern
• Western honey mesquite
• Western Islands
• Western Isles
• western kingbird
• western ladies' tresses
• western larch
• western lowland gorilla
• Western Malayo-Polynesian
• western meadowlark
• Western mountain ash
• western mugwort
• western narrow-mouthed toad
• western omelet
• Western paper birch
• Western pasqueflower
• western pipistrel