phenom, phenomena, phenomenon

Phenomenon is singular.

• The blended family is a recent social phenomenon.
• The Beatles were a music phenomenon in the 1960s.
• Tropical cyclones are a rare phenomenon in Canada.

Although the plural form phenomenons is sometimes used to describe extraordinary objects, events or persons, phenomena is the recommended plural. (Note that phenomenas is a non-standard plural.)

• Two categories of phenomena (not phenomenas) make up electromagnetic research.

The North American slang term phenom, meaning “prodigy,” is used mainly in sports and entertainment.

• Canadian athlete Alexandre Despatie is a diving phenom.