Someone told me it was an abreviation for hydroponics but I have also heard it is its own type of weed, could someone tell me?

Abbreviation for "hydroponic".

Sometimes slang for good weed. It ACTUALLY is short for "hydroponic" which is a method of growing weed. Anyone who tells you Dro is a strain (type of weed) is mentally retarded.

I wouldn't say mentally retarded, I would say misinformed. It's just short for hyrdroponically grown marijuana. Also called hydro.

dro is what most people call really good weed although i hate the term