The difference between stationery and stationary
It is not the meaning of these two that is ever confused, merely the spelling.
stationery (noun)—a piece of writing equipment, utensil
Caroline unlocked the door of the stationery cupboard and went in to fetch a box of pencils.
Lizzy was obsessed with stationery.
stationary (verb)—not moving
The police car drew up beside the stationary vehicle.
The train had been stationary for just a minute before moving on and continuing its journey.