n.
a perceptual structure; "the composition presents problems for students of musical form"; "a visual pattern must include not only objects but the spaces between them"
n.
the phonological or orthographic sound or appearance of a word that can be used to describe or identify something; "the inflected forms of a word can be represented by a stem and a list of inflections to be attached"
n.
an arrangement of the elements in a composition or discourse; "the essay was in the form of a dialogue"; "he first sketches the plot in outline form"
n.
(physical chemistry) a distinct state of matter in a system; matter that is identical in chemical composition and physical state and separated from other material by the phase boundary; "the reaction occurs in the liquid phase of the system"