Lesser or smaller in amount, extent, or size. Lesser in importance, rank, or stature: a minor politician. Lesser in seriousness or danger: a minor injury. Law Being under legal age; not yet a legal adult. Chiefly British Relating to or being the younger or junior of two pupils with the same surname. Of or relating to a secondary area of academic specialization. Logic Dealing with a more restricted category. Music Relating to or being a minor scale. Music Less in distance by a half step than the corresponding major interval. Music Based on a minor scale: a minor key. One that is lesser in comparison with others of the same class. Law One who has not reached full legal age. A secondary area of specialized academic study, requiring fewer courses or credits than a major. One studying in a secondary area of specialization: She is a physics minor. Logic A minor premise. Logic A minor term. Music A minor key, scale, or interval. Sports The minor leagues of a sport, especially baseball. To pursue academic studies in a minor field: minored in music.