Pending transaction
A purchase or deposit that has been approved but not fully processed, so it can still change or drop off before it posts.
Pending items show up in your banking app and reduce your available balance, but they are not final. Once processed, they post to the account and appear on your statement.
Amounts can change while pending. A restaurant bill can grow when the tip is added, and a gas station hold is often replaced by the real amount.
Example
A $45 pending restaurant charge posts two days later as $54 after a $9 tip is added.