Step by Step Comprehensive Detailed Explanation: In the context of ServiceNow IT Service Management, specifically within the service portfolio taxonomy, a ‘leaf node’ can be associated with a service. The service portfolio taxonomy is a hierarchical structure that organizes the services offered by an organization. At the top of this hierarchy are broad categories or ‘nodes,’ which are then broken down into more specific ‘leaf nodes.’ These leaf nodes represent individual services or offerings that are the most granular level within the taxonomy. Associating a service with a leaf node allows for detailed tracking and management of that particular service within the larger portfolio.

References: The information is based on the ServiceNow product documentation and resources available on their official support and documentation portals, which detail the service portfolio management taxonomy and its components123.