There something about the tiny parcels, these translucent pillows stuffed with goodness, called dim sums. Healthy and nutritious, they are a great crowd pleaser and the perfect things to order when you are in the mood for a light meal and yet want variety.
Momos are dumplings served in Tibet, Nepal and North East India. The wrapper is made up of refined wheat flour and water, unlike that of dim sums which can be made with any kind of flour like potato flour, rice flour, etc.
The latter actually doesn't refer to a particular dish but the concept of 'snacks' in Cantonese. Bite sized items served with tea are referred to as dim sum. Dim sum includes dumplings but can also include other items like custard buns, etc. Siu Mai is a type of dumpling which is open at the top, traditionally with a pork filling. Bao refers to a steamed bun with a meat or vegetable filling. Har Gao on the other hand has very thin and translucent skin (which often runs the risk of falling apart under your chopsticks).