Refers to a group that is smaller in number or influence within a larger population, often in social, political, or organizational contexts.
At that meeting, the minority opinion was also respected.
He always belongs to the minority.
少数派 refers to the minority group or faction itself, while 少数意見 refers specifically to the opinion that group holds.
Compound of 少数 (しょうすう, 'small number') and 派 (は, 'group, faction').