1. By means of osmosis

See also: osmotic

• Western rattlesnake
• western red cedar
• western red-backed salamander
• western redbud
• Western ribbon snake
• Western Roman Empire
• Western saddle
• Western Sahara
• Western Samoa
• Western Samoan monetary unit
• Western sand cherry
• western sandwich
• western saxifrage
• Western silvery aster
• western skink
• western spadefoot
• western tamarack
• western tanager
• western toad
• western United States
• western wall flower
• western wheatgrass
• western whiptail
• western white pine
• western wood pewee