lineaments

This term refers to the distinctive contours or outlines of a person's face, often used to describe the structural features that make a face recognizable. It carries a formal, literary, or artistic register, evoking the image of a sketch or a blueprint of a human countenance rather than a casual description of appearance.

Beyond physical anatomy, the word is used figuratively to describe the essential characteristics or the general outline of a plan, idea, or system. In this abstract sense, it suggests the primary framework or the "skeleton" of a concept before the finer details are filled in.