Structural:
- Structures typically answer the question of “what” in a design, and are typically described using nouns and adjectives.
- Structures are physical components, logical objects, attributes, fields, or arrangements of other structures within a design.
Behavioral:
- Behaviors typically answer the questions of “how” and “when” in a design, and are typically described using verbs and adverbs
- Behaviors are an action, force, process, or control that is exerted on or by a structure with respect to the structure's external environment.