Refers to small, rounded stones often used in gardens, paths, or as decorative ground cover. The kanji 玉 suggests rounded, jewel-like pebbles.
I spread gravel in the garden.
玉砂利の上を歩くと音がする。
Walking on the gravel makes a sound.
Compound of 玉 (tama, 'ball, jewel') and 砂利 (jari, 'gravel'), referring to rounded, pebble-like gravel.