It is definitely not gambling because you buy something and you own coins so it is in your hands to sell it or not because gambling is just to bet on something.
There is not even 0.1% similarity between bitcoin and gambling. Gambling is something really very destructive in nature whereas bitcoin is highly productive. It has helped masses in improving their financial conditions. Countless people have started their businesses with the help of bitcoin.
It is also playing very important role in reducing unemployment on the other hand, gambling makes people sell all they have just for an addiction.