noun

• (geometry) A surface of revolution formed by rotating a segment of a line around another line that intersects the first line.
• (geometry) A solid of revolution formed by rotating a triangle around one of its altitudes.
• (topology) A space formed by taking the direct product of a given space with a closed interval and identifying all of one end to a point.
• Anything in the general shape of a cone.

verb

• (transitive) To fashion into the shape of a cone.
• (intransitive) To form a cone shape.
  "Under the old method the material coned at the bottom of the borehole and as a result it would not go under houses and buildings."
• (frequently followed by "off") To segregate or delineate an area using traffic cones.
  "The area occupied by the works should be coned off and the usual advance warning signs should be provided on all approaches"