URL encoding
URL encoding stands for encoding certain characters in a URL by replacing them with one or more character triplets that consist of the percent character "%" followed by two hexadecimal digits. The two hexadecimal digits of the triplet(s) represent the numeric value of the replaced character.

URL Rewrite
URL rewriting, is the process of altering (often automatically by means of a program written for that purpose) the parameters in a URL (Uniform Resource Locator).