Everything must have a dimension to lock it in place- blue lines indicate something that hasn’t been dimensioned

Coincident – Where two points join together

Concentric – Have the centre in the same location, share the same centre point.

Co-linear – Same angle of a line for example

Co-radial – same radius for the same point

Equal – Identical sizes, when linked they will change so very useful for changing lots of holes on board for example

Parameter – For circles: Diameter or Radius, position of centre on a face