D defs.my
Entry 1 sense Webster, 1913

Precursor

/prĭ-kûr′sər/ · Pre·cur·sor · IPA /pɹɪˈkɜː.sə/
01 n. One who, or that which, precedes an event, and indicates its approach; a forerunner; a harbinger.
  1. 1.
    One who, or that which, precedes an event, and indicates its approach; a forerunner; a harbinger.
    “Evil thoughts are the invisible, airy precursors of all the storms and tempests of the soul.” — Buckminster.