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)

• rarefactions
• rarefactive
• rarefiable
• rarefied
• rarefies
• rarefy
• rarefying
• rare gas
• rare groove
• rarely
• rareness
• rarenesses
• rarer
• rare-ripe
• rarest
• raring
• rarities
• rarity
• ras
• RAS
• rasae
• rascaille
• rascailles
• rascal
• rascaldom