A Wire Point is a collection of 3D points in space that define wire positions in Lineardraft. These can also be referred to as wire registration points - locations where electrified wires are suspended above a rail track.
For example, a Wire Point for a Catenary System has two 3D points in space, while a Wire Point for an Auxiliary Wire has only one 3D point - at least normally in the UK!
Depending on the complexity of the System Design Catalogue you're using, you might find Wire Points made up from different numbers of 3D points.