attachment
n. C / Un. a computer file that you send together with an email. It can also mean an extra part that you connect to a machine to make it do a specific job.
n. a supplementary document or digital file appended to an electronic communication, or a removable accessory affixed to a piece of equipment.
Please open the attachment to see the new schedule.
The vacuum cleaner comes with a special brush attachment for removing pet hair from the sofa.
Because the server automatically strips executable files from incoming messages to prevent malware infections, you must upload the software update to a shared drive rather than sending it as an attachment.
From French attachement. By surface analysis, attach + -ment.
Commonly pairs with the verbs 'open', 'download', or 'send' in computing contexts.