Dear Navin
Shuttering or form work is the term used for temporary timber, plywood, metal or other material used to provide support to wet concrete mix till it gets strength for self support. It provides supports to horizontal, vertical and inclined surfaces or also provides support to cast concrete according to required shape and size. The form work also produces desired finish concrete surface. The terms used have no any basic differance.The word centering denotes that the supports of form work or shuttering shuold be truly vertical which takes the load of the form work and concrete except the side supports.