precursor /prē-kûrˈsər/

1. Something that exists or goes in advance of another
2. An indication of the approach of an event
3. A forerunner, herald or harbinger
4. A predecessor
5. A substance from which the one in question is derived or manufactured (chem)

• reverists
• revers
• reversal
• reversal colour film
• reversals
• reverse
• reversed
• reversed discrimination
• reverse discrimination
• reversedly
• reverse engineering
• reverse gear
• reverse genetics
• reverseless
• reversely
• reverse osmosis
• reverse pass
• reverse passes
• reverse printer
• reverse printers
• reverse proxies
• reverse proxy
• reverser
• reversers
• reverses