1. (n.) Anything in three parts or leaves.

2. (n.) A writing tablet in three parts, two of which fold over on the middle part.

3. (n.) A picture or altarpiece in three compartments.

Domesday Book abstract abstraction account book address book adversaria album altarpiece annual appointment calendar appointment schedule blankbook block print blotter calendar cashbook catalog classified catalog clover collage color print commonplace book copy court calendar cyclorama daub daybook desk calendar deuce-ace diary diptych docket engagement book engraving fresco icon illumination illustration image journal leash ledger likeness log logbook loose-leaf notebook memo book memorandum book memory book miniature montage mosaic mural notebook pad panorama petty cashbook photograph picture pocket notebook pocketbook police blotter print representation reproduction scrapbook scratch pad set of three shamrock spiral notebook stained glass window stencil still life table tableau tablet tapestry tercet ternary ternion terzetto three threesome tierce trefoil trey triad trialogue triangle tricorn trident triennium trihedron trilogy trimester trine trinity trinomial trio triphthong triple crown triple threat triplet triplopy tripod trireme triseme triskelion trisul triumvirate triunity trivet troika wall painting workbook writing tablet yearbook