main / major / specialize / line of work / field-of-endeavor

This sign means "major (in school), main, field of work, specialize..."

MAIN/major/line of work/field of discipline and other related concepts:
The right flat hand moves forward along the top of the stationary left flat hand.

PROFESSION:
To indicate a "professional," add the "AGENT" sign.

Variation: Some people do this sign using an "index finger" on the dominant hand or even with both fingers in "index finger handshapes.

American Sign Language University ASL resources by Lifeprint.com Dr. William Vicars