Definition of funicular from Wiktionary:

A particular type of rail transit system which ascends a steep urban or mountain incline, having usually two cars sharing a single track, with the cars linked by a moving cable and an arrangement of pulleys such that the descending car assists in the hoisting of the ascending car, i.e. the two cars serve as counterweights for each other.

Aerial tramways are often referred to as funiculars but should instead be tagged gondola_lift and aerial_lift as they do not ride on rails. Both funicular railways and aerial tramways should be tagged cable_transport.