So wherever you see the word 'rounds' bandied about, you can take it to mean coins.
Silver coins come in all sizes from less than one ounce to 100 ounce and over.
Some examples of silver rounds are:
There are many more.
Basically the 1 ounce coin contains one ounce of pure silver and sometimes an alloy to give it more durability, usually copper. The silver content is usually refined to a purity of 99.9 percent or more.
Each country has their own unique design and beauty for their coins.
Silver round purchases should ideally be proof sets or at least Brilliant Uncirculated. They should come sealed against tarnish and have no nicks, scratches or other blemishes and should look perfect.
Silver coins should not be cleaned. This is a highly specialized activity and cleaning silver almost always results in a loss of value for that coin.
Collecting silver rounds can be a very pleasurable activity not only for the beauty of the coins but also for the knowledge that one is providing for ones future by collecting silver rounds.