1.Definition: highest in pitch or chief among parts or voices or instruments or orchestra sections
"First soprano", "The first violin section", "Played first horn"
2.Definition: indicating the beginning unit in a series
3.Definition: preceding all others in time or space or degree
"The first house on the right", "The first day of spring", "His first political race", "Her first baby", "The first time", "The first meetings of the new party", "The first phase of his training"
4.Definition: ranking above all others
"Was first in her class"
5.Definition: serving to begin
"The first verse"
6.Definition: serving to set in motion
"His first (or maiden) speech in Congress"