WordWeb Online

1. Show a response or a reaction to something
   - respond, reply
    
2. Act against or in opposition to
   "She reacts negatively to everything I say";
   - oppose
    
3. (chemistry) undergo a chemical reaction; react with another substance under certain conditions
   "The hydrogen and the oxygen react"

Derived forms: reacts, reacting, reacted

Type of: act, change state, move, turn

Encyclopedia: React