底そこ

noun

bottom; sole

Refers to the lowest part or underside of something; also used for the sole of a foot or shoe.

• 海うみの底そこにはたくさんの生いき物ものがいる。

  There are many creatures at the bottom of the sea.

• 靴くつの底そこがすり減へってきた。

  The soles of my shoes are wearing out.