say it: pur-puhn-DI-kyuh-lur
perpendicular is a noun and adjective meaning "a straight line at right angles to another line". It carries 7 recorded senses.
a straight line at right angles to another line
a Gothic style in 14th and 15th century England; characterized by vertical lines and a four-centered (Tudor) arch and fan vaulting
a cord from which a metal weight is suspended pointing directly to the earth's center of gravity; used to determine the vertical from a given point
an extremely steep face
intersecting at or forming right angles
“the axes are perpendicular to each other”
Forms marked · are formed by the regular rule rather than recorded in the source data. English keeps a few hundred irregulars and the rest follow the pattern, so the rule is right far more often than not — but it is a rule, and the mark says so.
Definitions, synonyms and semantic relations for perpendicular come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.