Mail vs. Post
In the letters-and-packages sense, “mail” and “post” overlap but differ by regional preference. Cambridge treats “post” as mainly British and gives “mail” as the usual US counterpart; the comparison does not extend to unrelated senses of “post.”
For letters, packages, and the delivery system, “mail” is general and especially the US default; “post” is mainly British in this sense. Both words have other unrelated meanings.
Key details
Choose the right form
| Meaning / context | Use | Decision |
|---|---|---|
| letters/packages or their delivery system in US-oriented English | Use “mail” as the ordinary US form. | |
| the same postal sense in UK-oriented English | post | “Post” is a normal British choice. |
| email, job posts, fence posts, or other unrelated senses | check the specific sense | Do not transfer the regional postal comparison to unrelated meanings. |
Quick tests
Decision test
Are you talking specifically about physical letters, parcels, or the postal delivery system?
If yes: Choose “mail” for US-oriented wording or “post” for UK-oriented wording.
If no: If the sense is unrelated to postal delivery, decide from that separate meaning.
Caveat: This page is limited to physical postal correspondence and delivery; neither word is a universal substitute for all senses of the other.
Examples
The package arrived in the mail this morning.
“Mail” is the ordinary US-oriented postal term.
The parcel should arrive by post tomorrow.
“Post” is a normal British postal term.
Please send the signed form by mail.
The sentence uses the postal-delivery sense rather than an unrelated meaning of “post.”
Further guidance
Core difference
Use “mail” as the ordinary US form.
Fast Test
Choose “mail” for US-oriented wording or “post” for UK-oriented wording. If the sense is unrelated to postal delivery, decide from that separate meaning.
Usage Boundary
This page is limited to physical postal correspondence and delivery; neither word is a universal substitute for all senses of the other.
Sources and evidence
Sources are shown with the role they play in this guide. Historical or style-sensitive claims are kept within the evidence boundary described above.
- mail — Cambridge Dictionary (opens in a new tab)Cambridge University Press · Mail covers letters/packages and the delivery system; Cambridge marks UK post as an equivalent in this sense.
- post — Cambridge Dictionary (opens in a new tab)Cambridge University Press · Post for letters and the delivery system is mainly UK, with US usually mail; the verb post is likewise marked UK where US has mail.