底そこマチ

noun

bottom gusset

Refers to the gusset (extra piece of fabric) inserted at the bottom of a bag or pouch to create depth and volume.

• このトートバッグは底そこマチが広ひろいので、たくさん入はいります。

  This tote bag has a wide bottom gusset, so it can hold a lot.

• 底そこマチ付つきのポーチは見みた目めより収しゅう納のう力りょくがあります。

  A pouch with a bottom gusset has more storage capacity than it looks.