cofactor /kō-fakˈtər/

1. A factor which occurs along with other factors in multiplication
2. A nonprotein organic molecule or a metallic ion that binds with an enzyme and is essential to the enzyme's activity (biology)

• spillings
• spill one's guts
• spill over
• spillover
• spillovers
• spills
• spill-stream
• spill-streams
• spill the beans
• spillway
• spillways
• spilosite
• spilosites
• spilt
• spilth
• spilths
• spin
• spina
• spina bifida
• spinacene
• spinaceous
• spinach
• spinach beet
• spinach beets
• spinaches