The Collaborative International Dictionary of English v.0.48:

Schema \Sche"ma\, n.; pl. Schemata, E. Schemas. [G. See
   Scheme.] (Kantian Philos.)
   An outline or image universally applicable to a general
   conception, under which it is likely to be presented to the
   mind; as, five dots in a line are a schema of the number
   five; a preceding and succeeding event are a schema of cause
   and effect.
   [1913 Webster]

WordNet (r) 3.0 (2006):

schema
    n 1: an internal representation of the world; an organization of
         concepts and actions that can be revised by new information
         about the world [syn: schema, scheme]
    2: a schematic or preliminary plan [syn: outline, schema,
       scheme]

Moby Thesaurus II by Grady Ward, 1.0:

110 Moby Thesaurus words for "schema":
   alphabet, approach, arrangement, art, attack, blueprint,
   blueprinting, calculation, catalog, catalogue raisonne,
   charactering, characterization, chart, charting, choreography,
   conception, contrivance, conventional representation,
   dance notation, delineation, demonstration, depiction, depictment,
   design, device, diagram, disposition, drama, drawing, enterprise,
   envisagement, exemplification, figuration, figuring, foresight,
   forethought, game, graph, graphing, ground plan, guidelines,
   hieroglyphic, iconography, idea, ideogram, illustration, imagery,
   imaging, intention, layout, letter, limning, lineup, logogram,
   logograph, long-range plan, map, mapping, master plan, method,
   methodology, musical notation, notation, operations research,
   organization, outline, pictogram, picturization, plan, planning,
   planning function, portraiture, portrayal, prearrangement,
   prefigurement, presentment, printing, procedure, program,
   program of action, projection, rationalization, realization,
   rendering, rendition, representation, schedule, schematism,
   schematization, scheme, scheme of arrangement, score, script,
   setup, strategic plan, strategy, syllabary, symbol, system,
   systematization, tablature, table, table of contents,
   tactical plan, tactics, the big picture, the picture, way,
   working plan, writing



The Free On-line Dictionary of Computing (30 December 2018):

schema

   1.  database schema.

   2.  axiom schema.

   3.  XML schema.