Insertion/ɪnˈsɜːrʃn/ Definition 1 of 4Pro Tip 1/3Physical Act Focuses on the tangible action of putting one thing inside another. Following the instructions, he completed the insertion of the key into the lock. Pro Tip 2/3Possibly Painful Used in clinical contexts, insertion might involve some discomfort. Despite her anxiety, the insertion of the IV line was barely noticeable. Pro Tip 3/3Precision Required The word often implies a need for care or accuracy in the action. The craftsman's steady hands allowed for the precise insertion of the delicate part.