A noun (often as a suffix) indicating a change or alteration — the act or result of replacing or changing something.
設計の替え案をいくつか用意して会議で示した。
I prepared several alternative designs and presented them at the meeting.
資料の一部に替えが必要だと指摘された。
I was told that part of the materials needed to be changed.
A substitute, spare, or replacement item (e.g., a change of clothes, a spare part).
着替えをバッグに入れておいてください。
Please put a change of clothes in your bag.
替えの電池が切れてしまったので、買いに行った。
My spare battery ran out, so I went to buy one.
Used (usually written 換え) in contexts of exchange — referring to exchanging currencies or the act/ratio of exchange.
空港の窓口でドルへの替えをお願いした。
I asked the airport counter to exchange my money into dollars.