centre-to-centre distance(Centre-to-centre distance is a concept for distances, also expressed as hart distance. It is also called pitch. It is the distance between the centre (the heart) of a column or pillar and the centre (the heart) of another column or pillar. By expressing a distance in c.t.c., one can measure distances between pillar and columns with different diameters without confusion. WAD Alexander Demidov)
