The word “muscle” is derived from the Latin word “musculus,” which is a diminutive form of “mus,” meaning “mouse.” The etymology traces back to the way muscles were observed to move and contract in a manner that resembled the movement of a mouse scurrying under the skin. Thus, “musculus” can be literally interpreted as “little mouse,” highlighting how early anatomists related the appearance and behavior of muscles to that of small animals. This connection illustrates both the descriptive nature of language and the creativity of those who named anatomical structures in the past.