Someone who is in third grade.

(sports) A unit of players that plays behind the first and second strings; a junior varsity team.

belonging to the third string of a team; one who plays behind the first and second strings. / a substitute or replacement.

(idiomatic) Of a decidedly lower quality or condition.

Most inferior in quality or standing.

(bowed string instruments) ring finger / (keyboard instruments) middle finger

A musical interval with exactly three half steps that spans two degrees of diatonic scale.

(music) A musical interval of the Western twelve-semitone system consisting of four semitones and spanning three degrees of the diatonic scale. Major scales are so named because of the major third interval between the tonic and mediant of a major tonic triad. It is enharmonically equivalent to a diminished fourth.

plural of third eye

(politics) The socialist practice of supporting Third-World countries, especially in their struggle for liberation from colonial powers