A surface of revolution formed by rotating a segment of a line around another line that intersects the first line. • A solid of revolution formed by rotating a triangle around one of its altitudes. • 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. • The fruit of a conifer or a similarly shaped fruit or flower head of certain other plants, such as banksias and proteas. • A unit of volume, applied solely to marijuana and only while it is in a smokable state; roughly 1.5 cubic centimetres, depending on use. • An ice cream cone. • A traffic cone. • A passenger on a cruise ship (that needs to be navigated around). • A cone-shaped cannabis joint. • A shell of the genus Conus, having a conical form. • Any of the small cone-shaped structures in the retina. • The bowl piece on a bong. • The process of smoking cannabis in a bong. • An object V together with an arrow going from V to each object of a diagram such that for any arrow A in the diagram, the pair of arrows from V which subtend A also commute with it. (Then V can be said to be the cone’s vertex and the diagram which the cone subtends can be said to be its base.) • A set of formal languages with certain desirable closure properties, in particular those of the regular languages, the context-free languages and the recursively enumerable languages.