Architecture, architectonics and their corresponding adjectives architectural and architectonic are often indistinguishable, but they tend to diverge in emphasis.
The nouns mean the science of planning and building structures (as churches, houses, bridges, and ships) that involve problems of artistic design, engineering, and adaptation to the ends in view.
In general use architecture and hence architectural often suggest that artistry or beauty in design is the end and goal of the architect; in technical use they stress design as the result of attention to practical as well as artistic ends and imply that the profession is both a science and an art.
Architectonics and its corresponding adjective architectonic place the emphasis on constructive skill; they suggest attention to the framework, skeleton, or supporting structure, sometimes without reference to the details necessary for the completion or elaboration of the structure; when one speaks of Chartres Cathedral as a triumph of architecture, he calls attention to its beauty of design and ornamentation; but when one speaks of it as a triumph of architectonics, he calls attention to it as a great work of engineering where the supporting parts of pillars, props, and ribs are united so as to form a stone skeleton capable of carrying the enormous weight of stone roof and high towers yet permitting many windows in its enclosing walls.
Architectonics and its adjective are far more common in extended use than architecture and architectural, for the latter seldom escape their suggestions of building with stone, wood, or steel.
Architectonics and more especially architectonic, on the other hand, often are referable to a system of ideas or philosophy or to a work of art and especially to an epic or a poetic drama where there is not only perfect articulation of parts but their combination into an integral or organic whole.
- creative energy . . . is . . . architectonic, and it imposes upon the lyric impulse an ordered sequence and an organic unity
—Lowes - Dante’s . . . architectonic[s] of the relationships of authority and obedience
—Knox