What’s the difference between stationary and stationery?

writ-write-wrote:

Stationary means ‘fixed in one place and not moving’ while stationery means ‘the paper and envelopes used for writing correspondence’.

You can use the a in stationary to remember it is the adjective. Stationery is a noun. Another mnemonic to help you is: let the ar near the end of stationary remind you of ‘at rest’ and the e near the end of stationery stand for ‘envelope’.