This DHFT Application Note defines Structural Drift in Legal Practice as a domain-specific application instance of Structural Drift within legal systems. The document applies Dimensional Human Field Theory (DHFT) under canonical constraint and identifies Structural Drift as pre-failure system degradation under conditions of load, capacity limitation, and boundary strain. Legal practice is treated as an application surface and does not limit the cross-domain scope of Structural Drift. This document does not define, modify, or extend canonical DHFT system structure. System Relation This document is part of the Dimensional Human Field Theory (DHFT) Projection Series. Related technical documents include:Dimensional Human Field Theory (DHFT): Architectural Identification of a Closed Explanatory System — DOI: 10.5281/zenodo.19075948DHFT Technical Note: Admissibility Conditions: Valid System Description — DOI: 10.5281/zenodo.19572188 All documents preserve invariant variables, structural relations, and constraint conditions. All admissible system descriptions reduce to Load (L), Capacity (C), and Boundary (B). OSF Repository: https://osf.io/9psmd/