envelope

An envelope is a specific kind of container — a paper or material pouch for letters and documents. A competent speaker would call an envelope 'a container' (Law 9). The direction is specific→general: envelope→container.

An envelope is designed and maintained for the sake of communication — its purpose is to contain, protect, and enable the delivery of written correspondence. Per Law 8d: servant (envelope) → master (communication). Remove communication as a practice and an envelope ceases to have any function.

An envelope IS a specific kind of tool — an artifact that extends human capacity for communication through containment and protection. Competent-speaker test: an envelope is a tool (in the broad kingdom sense per Law 11c).

The envelope (ADSR model) contains attack as a constituent phase — the attack is literally one part inside the whole envelope structure. A competent speaker says 'the envelope has an attack phase.' Files Law 10: CONTAINS is whole-and-part only.

attack is defined in audio/signal processing as the initial rise phase OF an amplitude envelope. The removal test: remove the concept of envelope and attack as an audio concept loses its operational meaning — there is no framework within which attack operates. This is operational dependency, not meta-level (Law 8b): attack is a PART-CONCEPT of the envelope, not just named alongside it. Files the direction: attack→envelope because attack needs the envelope concept to function.

Test: amplitude-envelope is a specific kind of envelope. A competent speaker would call an amplitude-envelope 'an envelope' (specifically, the amplitude type). The general category is 'envelope' (a curve outlining extremes), and amplitude-envelope pins the specific domain (signal amplitude).