noun
General term for what is left over, often used for quantities, parts, or amounts.
予算の残部は来月に繰り越される。
The remainder of the budget will be carried over to next month.
noun
remaining copies; copies still in stock
Specifically refers to unsold or undistributed copies of books, magazines, or other printed materials.
この雑誌の残部はあとわずかです。
Only a few copies of this magazine are left.