What is the meaning of perpendicular?

noun

• 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.
  • synonyms: perpendicular style, English-Gothic, English-Gothic architecture
• 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.
  • synonyms: plumb line
• An extremely steep face.

adjective

• Intersecting at or forming right angles.
  • usage: "the axes are perpendicular to each other"
• At right angles to the plane of the horizon or a base line.
  • usage: "a vertical camera angle"; "the monument consists of two vertical pillars supporting a horizontal slab"; "measure the perpendicular height"
  • synonyms: vertical
• Extremely steep.
  • usage: "the great perpendicular face of the cliff"