It does not quite refer to my little pony, it’s more of a corporate cultural term.
You can also say “velocity”, you can say “agility” to mean the same concept.
It’s how quickly and effectively you get stuff done. If the sprint is 2 weeks and you pack two sprint’s worth of work into one, that’s high cadence.
If you are able to bring teammembers together to solve a challenging challenge, it’s cadence.
You say, “we like the increased cadence this fiscal quarter.”
It generally refers to productivity. It is one of the highest states to aspire for.