sectional (adj.)

1806; see section (n.) + -al (1). Noun meaning "piece of furniture composed of sections which can be used separately" is attested by 1961, from sectional seat, sectional sofa, etc. (1949).

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Definitions of sectional from WordNet
sectional (adj.)
relating to or based upon a section (i.e. as if cut through by an intersecting plane);
a sectional view
sectional drawings
sectional (adj.)
consisting of or divided into sections;
a sectional sofa
Synonyms: sectioned
sectional (adj.)
related or limited to a distinct region or subdivision of a territory or community or group of people;
sectional tensions arose over slavery
sectional (n.)
a piece of furniture made up of sections that can be arranged individually or together;