D defs.my
Entry 2 senses Webster, 1913

Phenomenon

/fən-äm'-ən-änˌ/ · Phe·nom·e·non · IPA /fəˈnɑ.məˌnɑn/
01 n. An appearance; anything visible; whatever, in matter or spirit, is apparent to, or is apprehended by, observation; as, the phenomena of hea…
pl. Phenomena ((#))
  1. 1.
    An appearance; anything visible; whatever, in matter or spirit, is apparent to, or is apprehended by, observation; as, the phenomena of heat, light, or electricity; phenomena of imagination or memory.
    “In the phenomena of the material world, and in many of the phenomena of mind.” — Stewart.
  2. 2.
    That which strikes one as strange, unusual, or unaccountable; an extraordinary or very remarkable person, thing, or occurrence; as, a musical phenomenon.