Puzzle of the Day

Shown above are examples of various notation systems for what? (Clarification: I am looking for one answer, not seven.)

Check back tomorrow for the answer, a shoutout to all the solvers, and a new puzzle!

Previous puzzle:

What well-known brand (which you could find in any supermarket) sounds like it ought to have a logo similar to the ones in yesterday's puzzle (1, 2), but was actually named for three patented ingredients which supposedly fight plaque?

(Four out of five ethicists agree that this isn't product placement since I wasn't paid to do it.)

Answer:

Trident gum! A trident is Poseidon's three-pointed spear, but in the case of the gum, it's also a pun (thanks to Leo for the link). The parenthetical was a reference to Trident's famous advertising slogan ("Four out of five dentists surveyed recommend sugarless gum for their patients who chew gum"), which helped Mr. Gregg, at least. Notice the very careful wording of that slogan.

Congrats to these folks who solved the puzzle, perhaps after chewing it over: Jessica, Maddy, Joshua Z., Leo S., Aditi, and Mr. Gregg!