A main road is called a Sai like Sai Song (2rd road) or Sai Sarm (3nd road).
A Soi as a small street off that main road.
A Moo is an even smaller street off a Soi.
So Moo10 is the 10th smaller street of a Soi, which is usually named. For example Soi17, Moo10.
Spelling not accurate...but that's how I pronounce it.