дагуул

[lamasu]

I've come across the mongolian word дагуул, which should means "fellow traveler", "companion" but also "moon", "satellite".

I think it is built on the verb дагах, meaning "to follow", right?

But there is a think I don't understand: what is the function of the suffix -уул in this case? It doesn't seem to me neither a causative suffix nor a plural suffix, so.. what is it?

[sharshuvuu]

Whatever it is, it's куул!

Шаршувуу

[Bor Chono]

Word уул can mean :
-mountain

-something that was first, Like : main plan is A but plan is changed into B. So old or original plan should be A.
Уул санаа = actual idea

Har(see)+uul =guard (someone who is watching land)
Sar(moon)+uul =inteligent, not dark (light in the darkness)
Daga(follow)+uul =something that follow
Garga(to put outside)+uul =tool that is used to put something outside...etc