Noun precursor has 3 senses
  1. precursor - a substance from which another substance is formed (especially by a metabolic reaction)
    --1 is a kind of
    substance, matter
  2. precursor, forerunner - a person who goes before or announces the coming of another
    --2 is a kind of person, individual, someone, somebody, mortal, human, soul
    --2 has particulars: predecessor
  3. harbinger, forerunner, herald, precursor - an indication of the approach of something or someone
    --3 is a kind of indication, indicant