The term 'Routine Part' can refer to a number of different things. In this particular crossword, the solutions are JOKE (4 letters), BIT (3 letters), and ONELINER (8 letters). A JOKE is a humorous statement or story that is intended to make people laugh. A BIT is a short performance or routine that is usually part of a larger show. A oneliner is a JOKE that is delivered in a single sentence. All three of these solutions can be used as part of a routine in a comedy show or other performance.