stationery or stationary?

It's easy to distinguish these two.

stationery is paper and writing materials that you used to buy at a stationer's  and the -ery ending is the same as you get with confectionery or bakery other products to buy.

stationery cupboard
wedding stationery

stationary means not moving and is usually applied to vehicles. Remember it by a stationary car

stationary traffic

stationery traffic

Test yourself

1. We need more station_ry.
2. Beware of station_ry vehicles.
3. Slow-moving or station_ry traffic.
4. The Station_ry Bike by Stephen King.
5. Personalised station_ry
6. Restoration of old internal combustion station_ry engines. 

Answers: paste them into FLIP

 ˙sǝuıƃuǝ ʎɹɐuoıʇɐʇs uoıʇsnqɯoɔ lɐuɹǝʇuı plo ɟo uoıʇɐɹoʇsǝɹ 6
ʎɹǝuoıʇɐʇs pǝsılɐuosɹǝd 5
˙ƃuıʞ uǝɥdǝʇs ʎq ǝʞıq ʎɹɐuoıʇɐʇs ǝɥʇ 4
˙ɔıɟɟɐɹʇ ʎɹɐuoıʇɐʇs ɹo ƃuıʌoɯ-ʍols 3
˙sǝlɔıɥǝʌ ʎɹɐuoıʇɐʇs ɟo ǝɹɐʍǝq 2
˙ʎɹǝuoıʇɐʇs ǝɹoɯ pǝǝu ǝʍ 1