ELI5: Explain Like I'm 5

Superparticular ratio

Well, a superparticular ratio is like sharing a cake with your friends. Let's say you have 1 cake and 2 friends, and you want to share it equally between all of you. That means each person will get 1/3 of the cake or a ratio of 1:3.

Now, let's say you have 1 cake and 3 friends. You still want to share it equally, but this time, each person will get 1/4 of the cake or a ratio of 1:4.

Notice how the denominator (the bottom number of the ratio) is always one more than the number of people sharing the cake? That's what makes it a superparticular ratio.

Superparticular ratios are used a lot in music, especially when tuning instruments. For example, the ratio of the frequency of one note to the next note on a piano is a superparticular ratio.

So, think of superparticular ratios as a way of dividing something up equally but in a very special way where the denominator is one more than the number of things being divided.