What are those type lenses called?

[round eyeglasses frames]

I would like to buy glasses online and don't know what to call them. I only need one for distance and no rx on reading portion I've seen,prescription glasses that have only an distance portion and no reading portion. I need to know what they are called so that I can search for them online.

[rx sunglasses]

I guess you are looking for Bifocals. But I don't think you will have any luck buying them online.They have to be specially made.
There will probably be someone at most optometrists or opticians who can figure out how to make it work for you.