1. (n.) An unusual or marvelous occurrence; anything observable\; as, the phenomenon of light; phenomena of imagination or memory.

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

abnormality actuality adventure amazement anomaly apparition appearance astonishing thing astonishment circumstance curiosity episode event exception experience fact false image figure form gazingstock hap happening happenstance image incident marvel marvelment matter of fact miracle mirage nonesuch occasion occurrence paradox particular peculiarity phantom phasm portent presence prodigy quite a thing rarity reality sensation shape sight singularity something else spectacle stunner turn of events uniqueness unusualness vision wonder wonderful thing wonderment