Gore refers to a panel in a garment. In Shoe term, a Gore is commonly an elastic panel stitched into either side of the vamp in order to make it more comfortable and easier to put on and take off.

A Gored skirt, on the other hand is a ytpe of skirt which is made of several vertical panels.
Other /More definition:
Gore refers to:

(1) an elastic panel stitched into either side of a shoe's vamp or a boot's shaft to make it more comfortable and easier to put on and take off.

(2) Fabric panels sewn into skirts that are intended to add gradual fullness to a garment. Skirts often consist of three (3) or more Gores. Gore allow a closer fit over the hips and then gradually flare out at the lower part of the garment to increase the fullness at the hemline.

Gore is also known as Godet, a long, narrow triangular cloth piece of fabric; usually seen on a skirt along the hem.