Basically grinding is nothing but removal of metal at a much faster rate than was earlier done with single edge tools such as chisels. Of course, grinding can be compared to a cutting tool such as a file having multiple edges rather than a chisel with a single edge, but with a much greater speed, material removal, accuracy, and surface finish.
However, at the same time it must be noted that it is more appropriate to link grinding to a finishing process rather than a manufacturing process, in the true sense of the word, though these terms are used alternatively in common usage. Apart from being used as material removal process, it is also used to sharpen the cutting edges of cutting tools and sharp objects such as knives, although the underlying process of material removal is the same, but with a different purpose - to produce a sharp edge rather than to reduce size.