A new-old word bromide

Toward the end of Rand's "The Fountainhead", the word "bromide" is used a lot. I've only ever heard it used in its chemical reference before. Never would have guessed it had a second meaning. bro·mide n. 1. a. A binary compound of bromine with another element, such as silver. b. Potassium bromide. 2. a. A commonplace remark or notion; a platitude. See Synonyms at cliché. b. A tiresome person; a bore. In the book it's used as both 2a and 2b. Mainly the former. Each time I come across it in the text, I become aware of the fact that I'm reading and I realize I wasn't seeing words until I hit it. It's not unlike a speed bump that you didn't notice and it jars you out of auto-pilot.