Holacracy Community of Practice Archive, 2015-2019 Community Holacracy Web Site

Yes, that's an appropriate way of understanding a role!

The nuances come when you need to decide how granular or broad a role should be, or simply when the work is unique enough that there is no clear 'industry standard' for how to split the work... but yes, as a general rule of thumb, a role is a "business function".