There is an old joke which goes as follows:
“It doesn’t matter how hard you push the envelope; it will always be stationary.”
One could argue that the joke works better spoken rather than written, as writing the joke down forces the writer down a particular path. Does the writer choose stationary or stationery?
I come across a small number of students each year who are unaware that there are two spellings of this identical-sounding word. Demonstrating the correct usage of the two spellings is quite straightforward:
“We need more envelopes for the stationery cupboard.”
“He drove into a stationary vehicle.”
Stationery, when spelt with an e, refers to office supplies, writing materials, paper, etc. Stationary, with an a, refers to an object that is not moving, such as a car or other vehicle. Stationery is also used to describe what an item is – this paper is stationery, whereas stationary is used to describe an item’s current lack of movement – this train is stationary.
One may wonder why two different spellings exist. The etymology of the words reveals that they have two different sources. The source of stationery is from the word stationer, a word originally meaning a publisher or a bookseller, hence its link to writing and paper. The source of stationary, however, is from the Latin word stationarius, used as a military term for soldiers assigned to a particular, presumably static station.
These two sources reveal something of the nature of the English language and how, over time, it has acquired words from a wide variety of sources.
If you are looking for a way to remember which is which, try this:
Stationery has an e as it refers to envelopes.
Stationary has an ar as it refers to cars.