補充

1. Origins, structure, and basic meaning

• Structure: 補充(ほじゅう) means replenishing an amount or content that has become insufficient.
• Basic usage: It is used to refill depleted items such as products on a shelf or water in a container. Typical patterns are 商品を補充する and 水を補充する.

2. Common pitfalls and similar expressions

• Remember the shortage being filled
  • It fits restoring something that has been used up or reduced better than supplying something entirely new.
• Difference from 追加
  • 追加(ついか) broadly means adding something to what is already there, while 補充 focuses on restoring a shortage to the needed level.