Single Origin Coffee means that the coffee comes from one particular region or province within that country. Since some countries are quite large, the coffees can vary in flavour depending on which part of the country they come from.
Single-origin coffees are for those who want to explore the intricacies of coffee. Similar to wine, different varieties of the coffee cherry, along with different climates, harvests, processing methods and even terroir, produce certain flavours. The flavours can be quite unique to a particular landscape or variety of coffee which is why you can enjoy searching for particular nuances.