A pre-authorization is a type of pending bank charge used to check an account for validity or approve funding for a purchase you attempt to make. We may pre-authorize an amount before you make a purchase, then submit a final charge later when your order ships to you. That final charge amount is often different from the pre-authorized amount.
Another type of pre-authorization charge is for a purchase that was approved but that won't be posted to your account until later (such as for an item that does not ship right away because it's on backorder). Keep in mind, a charge may be pending for a few days, which essentially holds the pending funds for the intended purchase but does not charge them permanently. Once the permanent charge is posted, the pre-authorization charge will "fall off" your account. (This can take up to 3-5 days.) Contact your banking institution if this does not occur.