Adding to your vocabulary is easier if you know meaning of common prefixes, which help you understand the meaning of words. The following list contains three common prefixes and their meanings:

  • Co- means "with." Variations include col-, com-, and con-. (cofounder, commemorate, concussion)

  • De- can mean “reduce,” “remove,” and “to get off of.” (decaffeinate, decapitate, deplane)

  • In- and its variations — em-, en-, il-, im-, and ir- — can mean "not," "in," "within," "put into," and "surround." (incapable, enrage, impassioned)