It's likely you're thinking of the popular children's television show "UmiZoomi".
The show features three characters:
* Milli (the pink character)
* Geo (the blue character)
* Bot (the yellow character)
They live in a world called "Umi City", and they use math and problem-solving skills to help people and solve problems.
So, "UmiZoomi" is simply the name of the show, not a word with a specific meaning.