There are three main terms you need to know when you’re talking about solid, 3D shapes.  The terms are edge, corner/vertex and face.  This diagram shows what each one of these is:

A face is a flat surface on a solid shape.  It has to be flat to count as a face.  The surface of a sphere for instance doesn’t count as a face because it is curved.  A face is a two dimensional shape – it has an area.  Sometimes they’re called sides instead of faces.

An edge means exactly the same as when we use it in everyday life, such as to describe the edge of a table.  Edges are the straight line bits between faces on a solid shape.  Edges have to be straight to count as edges.  An edge is a one dimensional line – it only has a length.

Corners are the pointy bits on a solid shape.  They are one dimensional points – they don’t have any length or area.  They are also called vertices (singular form ‘vertex’).