Noun

• S: (n) solo (any activity that is performed alone without assistance)
• S: (n) solo (a musical composition for one voice or instrument (with or without accompaniment))
• S: (n) solo (a flight in which the aircraft pilot is unaccompanied)

Verb

• S: (v) solo (fly alone, without a co-pilot or passengers)
• S: (v) solo (perform a piece written for a single instrument)

Adjective

• S: (adj) solo (composed or performed by a single voice or instrument) "a passage for solo clarinet"

Adverb

• S: (adv) alone, solo, unaccompanied (without anybody else or anything else) "the child stayed home alone"; "the pillar stood alone, supporting nothing"; "he flew solo"