The term 'TYPE OF RUNNER' can be answered by two crossword solutions: MILER (5 letters) and RUM (3 letters). A MILER is a type of runner who specializes in running races that are one mile long. This type of runner typically trains for longer distances, such as 5Ks, 10Ks, and half-marathons. A RUM is a type of runner who specializes in running races that are three miles long. This type of runner typically trains for shorter distances, such as sprints and 5Ks.