Beginning; origin; source of s.t.; the reason or cause of s.t. [This can be used interchangeably with "poonan"].
According to some, monkeys were the origin of man.
What's the cause of that person's death? This is the reason he died.
The variant, "poonan", can be used instead of "poon" with some of these meanings, but not with others. It cannot be substituted for rice husk, tree trunk; It can be substituted for source/beginning, cause/reason, and capital for investment.
To start doing s.t.; to get s.o. started doing s.t.
Soy bay moon-moonan kau nginum alak?
Who got you started drinking liquor?
Don't start smoking, lest your younger brother copy you.
After he got started (by someone) playing the guitar, now he loves it.