Okay kiddo, have you ever seen a thermometer before? It's a tool that measures how hot or cold something is. Well, a long time ago, people didn't have thermometers, so they had to come up with a way to measure how hot or cold something was by using their senses like touch or taste.
One of the ways they did this was by using something called "gradibus" which is a Latin word that means "steps." Imagine you are climbing a ladder, but instead of steps, it's like a ladder of measurements. Each step represents a different level of temperature.
So, let's say that the bottom step is really, really cold, and each step going up gets a little bit warmer. On the top step, it's really, really hot! People used these steps to help them understand how hot or cold something was without having to use a thermometer.
Nowadays, we have thermometers to tell us exactly how hot or cold something is, but back then, they had to use their senses and their ladders of gradibus to figure it out. Cool, huh?