Phenomenon

Part of speech: noun (n.)

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. That which strikes one as strange, unusual, or unaccountable; an extraordinary or very remarkable person, thing, or occurrence; as, a musical phenomenon.