Tamara,
Don't be afraid to ask us anything. None of us was born a quilter. The term block or blocking is also used in other crafts. It refers to making sure the finished product is square. Many, not all, quilts are made up of squares or other shapes formed into squares that are then sewn together until they are the size desired. Before the quilt sandwhich of top, batting and backing is put together we again try and square up the top by careful pressing and a little trimming if necessary. Fabric has a tendency to stretch especially if some of the edges end up on the bias. Bias means that the fabric was cut on the diagnol. If you have ever used a sewing pattern it is marked with big arrows that tell how to lay the fabric out so that bias does not interfere with the proper hang of the garmet.