The term ANATOMICAL BAG can be broken down into three parts: SAC, which is a three letter word, ANATOMICAL, and BAG. SAC stands for 'SACK, ' which is a type of BAG that is typically made of cloth or paper and used to store items. ANATOMICAL refers to the study of the structure of living organisms, including their organs, tissues, and cells. Finally, BAG refers to a container made of cloth, paper, or plastic, used to store items. Therefore, the term ANATOMICAL BAG can be defined as a SACK used to store items related to the study of the structure of living organisms.