There isn't any confusion over booms and yards - not on my watch.

A boom is found on the bottom of a fore and aft sail, where fitted.

A yard is found on the top of a square sail. (OK it is actually trapezoid but is is called square)

There are other types of spar which support sails - sprits for instance. I have never known a sailor to get them confused.

In the photo from Bill you can see stuns'l yards with rings, and also part of a stays'l.

Sigh.

Here's me with a dose of Sea Fever again.