The abbreviation for attachment is Att., commonly used in business letters and document references. The plural form Atts. indicates multiple attachments, while Attach. is recognised in certain legal citation conventions. These forms help identify supporting documents without writing the full word repeatedly, but their correct usage depends on the type of correspondence.
What Is the Correct Abbreviation for Attachment?
There are several documented forms, although they are not equally appropriate in every situation.
| Abbreviation | Meaning | Common Usage |
|---|---|---|
| Att. | Attachment | Business letters and document notations |
| Atts. | Attachments | Letters containing multiple attachments |
| Attach. | Attachment | Certain legal citations and document titles |
Att. and Atts. are recognised by the Government of Canada’s business-writing guidance for indicating documents accompanying a letter. Attach. also appears in The Indigo Book, a legal citation guide.
There is no single abbreviation required across all industries. In everyday communication, writing attachment in full is usually clearer.
What Does Attachment Mean?
An attachment is something added or connected to another item. In business communication, it usually refers to a document or digital file included with a message, letter or record.
For example, a job application may contain a résumé attachment, while an email to a client might include an invoice, spreadsheet or project proposal.
The word also has meanings outside office communication. A machine attachment is an additional component connected to equipment, while emotional attachment describes a personal bond.
However, Att. is best established as a document-related abbreviation. It should not automatically be used for every meaning of attachment.
How to Use Att. in Business Letters
In traditional business correspondence, an attachment notation tells the recipient that additional material accompanies the letter.
This notation is typically placed below the signature block, aligned with the left margin.
For example, the bottom of a letter might include:
Att. (1)
This indicates that one attachment accompanies the correspondence.
For multiple documents, the notation may appear as:
Atts. 3
This indicates three attachments.
If several supporting documents are included, a numbered list or descriptive titles make them easier to identify.
For example:
- Attachment 1 – Project Budget
- Attachment 2 – Work Schedule
- Attachment 3 – Supporting Documents
Numbering is especially helpful when the main letter refers to individual documents. The labels should match the actual materials supplied.
Attachment Abbreviations in Emails and Legal Documents
Business Emails
Although Att. is recognised in correspondence, it is generally unnecessary in the body of a modern email.
Instead of writing:
“Please review Att. 1.”
A clearer message would be:
“Please review the attached project proposal.”
The full word feels more natural and tells the recipient exactly what to look for.
The related word attached describes something already included with the message. You can explore the abbreviation for attached to understand how its shortened form is used in correspondence.
Legal and Administrative Documents
Legal documents sometimes contain numbered attachments that support an application, statement or other filing.
In legal citation conventions, Attach. may be used when abbreviating the word Attachment in a document title.
However, legal citation rules and court filing requirements are not necessarily the same. A particular court or organisation may require attachments to be identified as exhibits, schedules or other document types.
Always follow the applicable filing instructions instead of assuming that Att. or Attach. is acceptable everywhere.
Attachment vs. Attached vs. Enclosure
These terms are related, but they serve different purposes.
| Term | Meaning | Example |
|---|---|---|
| Attachment | The additional file or document | The attachment contains the invoice. |
| Attached | Describes something included or connected | The invoice is attached. |
| Enclosure | Material included with a letter or package | Enclosure: Signed application |
In traditional business letters, Enc. is an established abbreviation for enclosure.
The distinction between an attachment and an enclosure may depend on the organisation’s correspondence style. Some businesses use the terms broadly, while formal writing guides provide separate notations.
There is also a difference between attachment and received. An attachment is the item being sent, whereas received indicates that the item has arrived or been accepted.
For example, “Invoice attached” describes the sender’s action, while “Invoice received” acknowledges its arrival.
Common Mistakes When Abbreviating Attachment
The biggest problem with attachment abbreviations is not spelling but using them where their meaning is unclear.
1. Confusing Att. with Attn.
Att. can indicate attachment in correspondence, while Attn. means Attention and is used to direct a letter or message to a particular person or department.
For example, “Attn: Accounts Department” is an attention line, not an attachment reference.
2. Using Att. as a verb
“Please Att. the invoice” is incorrect in ordinary writing. Use “Please attach the invoice” because attach is the verb.
3. Using an unexplained abbreviation in formal documents
A label such as “Att. 2” may be clear within an established document system, but readers unfamiliar with the convention might prefer “Attachment 2 – Financial Statement.”
4. Referring to attachments that are missing
Before sending correspondence, confirm that every referenced file is included and correctly named. A clear abbreviation cannot compensate for a missing document.
Frequently Asked Questions
What does Att. mean at the bottom of a letter?
Att. can mean Attachment when it appears as a notation below the signature of a business letter. It indicates that additional material accompanies the correspondence. Its meaning is determined by its position and context.
What is the abbreviation for multiple attachments?
Atts. is a recognised plural form used in business-letter notation. For example, “Atts. 3” indicates that three attachments accompany the letter. Writing “Attachments: 3” is an equally clear alternative.
Is Attach. a recognised abbreviation for attachment?
Yes. Attach. appears in legal citation guidance as a shortened form of Attachment. However, it should not be assumed to be the preferred abbreviation in every legal document or business letter. Follow the relevant style guide.
Should I use Att. in an email subject line?
You can use Att. in an established internal system, but describing the actual file is generally more helpful. A subject such as “Revised Contract Attached” tells the recipient more than “Contract – Att.” and reduces ambiguity.
Is Att. the same as an email attachment icon?
No. Att. is a written abbreviation, while the paperclip icon in email applications represents the attachment feature or indicates that a message contains a file. Both relate to attachments, but they serve different purposes.
Final Thoughts
Att. is a recognised abbreviation for attachment in business correspondence, Atts. is used for multiple attachments, and Attach. appears in certain legal citation conventions. These forms are useful for compact document references, but the full word attachment remains the clearest choice for most modern emails and general professional writing.
