Artificial intelligent assistant

perpendicle

perˈpendicle Obs. rare.
  [a. OF. perpendicle (14th c. in Hatz.-Darm.), ad. L. perpendiculum plummet, plumb-line, f. *perpendēre, f. per- 2 + pendēre to hang. Cf. mod.F. perpendicule (16th c.), It. perpendicolo.]
  A plumb-line.

14.. in Halliwell Rara Math. (1841) 58 Come toward and go froward til þe perpendicle, þat es to say þe threde whereon þe plumbe henges falle vpon þe mydel lyne of þe quadrant. 1656 Blount Glossogr., Perpendicle, a plumb line,..with lead at the end. 1755 Johnson, Perpendicle, anything hanging down by a straight line. 1867 Smyth Sailor's Word-bk., Perpendicle, the plumb-line of an old quadrant.

Oxford English Dictionary

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