These 2 words mean pretty much the same thing. Often they can be used synonymously. However, if you want to stress the exceptional or noteworthy quality, then especial or especially is a better choice. If you want to stress the distinctive purpose of something, then special or specially is the word you are looking for. Example: This program has specially designed macros for word processors. (A distinctive purpose) Example: He did especially well in All-Star Game. (A noteworthy performance)