* Stationery (with an "e") refers to writing materials, such as paper, envelopes, pens, and pencils. Think of the things you'd find in an office supply store.
* Stationary (with an "a") means not moving or not changing position. It describes something that is still or fixed.
Example:
* "I need to buy some new stationery for my desk." (Referring to writing materials)
* "The car remained stationary at the red light." (Describing the car's position)