Grammar Wednesday #2

Today's tip is courtesy of my lifelong friend Amber, and is dear to my heart after all the years I spent working in social stationery:

How do you remember which spelling of "stationery/stationary" is the correct one in a given situation?

• Stationery that means paper you write on and send in the mail has an E in it, for ENVELOPE. Envelopes go in the mail!
• Stationary that means standing still and not moving is the other one. (You can also remember it with an A for stAnding still.)