the world > relative properties > order > agreement, harmony, or congruity > conformity to or with a pattern, etc. > [adjective] > conforming to a standard rule > conforming to rules of art or law (2)
That is according to recognized forms, or to the rules of art or law. Formerly occasionally const. †to.
transferred. Of or pertaining to, also strictly conforming to the ‘grammar’ or formal principles of an art.