[ad. OE. upflór: UP- 1.] A triforium.
This special application is derived from the use of the word with reference to the church at Glastonbury in the O. E. Chron. (Laud MS.), an. 1083.
1879. A. Taylor, Guienne, 12. Our ancestors … gave the triforium (then lately devised) the vernacular English name of ‘upfloor.’
1912. C. E. Power, Eng. Mediæv. Archit., I. 20. The ‘triforium chamber’ or ‘up-floor’ of monastic writers.
