(linear algebra) lower triangular matrix

the last volume in a two- or three-volume set

(linear algebra) triangular matrix

a line or queue, a procession in single file / a ceremonial procession / (mathematics) a matrix

line; queue; procession / matrix; array

lowest of its kind, the worst

(linear algebra) upper triangular matrix

the lower portion, end / lowness in degree or rank / the downstream portion of a river / the downriver area / the area farther from the capital / the last part of a month, year, etc.

the lower portion, base / under the influence of

down; below; beneath