noun
gakubori; background elements in traditional Japanese tattooing
Refers to the background designs (waves, clouds, rocks, etc.) in traditional Japanese tattoos (和彫り), as opposed to the main motif (主図).
和彫りでは、主図の周りに額彫りとして波や雲が彫られる。
In traditional Japanese tattooing, waves and clouds are carved as gakubori around the main motif.