a basic structure underlying a system, concept, or text.
Scrum doesn't say how to do anything. It provides a basic structure in terms of roles that must be fulfilled and events that must be held. The how comes from the people doing the work, and different fields have figure out different techniques or practices that tend to work, many of which can be used within the context of the Scrum framework.
I like to think of Scrum as a garden lattice. The lattice (Scrum) is the framework that underlies and supports the plants and flowers(the processes) that grow on top of it. The lattice influences the direction in which the plants and flowers might grow and the gardener may control what type of plants are used...or not used.
Scrum influences the processes with use of Scrum Pillars, Values, and Events. It can also make transparent existing processes that have been added to the framework that are not providing the desired outcomes.
Activities like Planning Poker may be a process that is attached to the Scrum Framework during Backlog Refinement to serve a certain purpose - create transparency around the difficulty and effort involved in the work. The team may inspect and adapt this process over time, however, the underlying framework remains the same.
yes, I agree with you that framework is a supporting a structure based on events, pillars and values, but I would also include artifacts, accountabilities and rules (i.e. Product backlog refinement), what do you think?