For the current, application I am working on, we have a prefix that identifies the application name (four lowercase letters). The reason for this is that our application must be able to co-exist with a legacy application in the same database, so the prefix is a must.
If we did not have the legacy constraint, I am quite sure that we would not be using a prefix.
After the prefix we usually start the SP name with a verb that describes what the procedure does, and then the name of the entity that we operate on. Pluralization of the entity name is allowed - We try to emphasize readability, so that it is obvious what the procedure does from the name alone.
Typical stored procedure names on our team would be:
shopGetCategories
shopUpdateItem