Stationary or Stationery?

When spelt with an 'a', Station a ry means to be still. This comes from the latin word meaning:motionless.

late 14c., "having no apparent motion" (in reference to planets), from Middle French stationnaire "motionless" and directly from Latin stationarius , from the stem of statio "a standing, post, job, position" (see station (n.)). Meaning "unmovable" is from 1620s. In classical Latin, stationarius is recorded only in the sense "of a military station;" the word for "stationary, steady" being statarius .

It turns out, Stationery comes from Stationary. Isn't that confusing?
Basically, back in the middle ages traders would visit villages and towns to sell their wares. However, books and various paper products in bulk can be pretty heavy - you wouldn't expect a travelling library by horse and cart going far! Due to this weight, many paper sellers would setup a more permanent location. Their shop was stationary, so these sellers became known as "stationers". Slowly over time, the products sold by stationers became known as stationery.

By definition, any item sold in a permanent shop could technically be called stationery... but wouldn't that be absolutely confusing?
' I bought you some lovely stationery for your new job ' . . . *hands over cans of beer*.

Oh well! Another fun fact that may come up one day in a distant pub quiz!