Definitions of solo:

• noun:   a flight in which the aircraft pilot is unaccompanied
• noun:   any activity that is performed alone without assistance
• noun:   a musical composition for one voice or instrument (with or without accompaniment)
• verb:   perform a piece written for a single instrument
• verb:   fly alone, without a co-pilot or passengers
• adjective:   composed or performed by a single voice or instrument

  Example: "A passage for solo clarinet"

• adverb:   without anybody else

  Example: "He flew solo"

• name:  A surname (very rare: popularity rank in the U.S.: #32805)