What is the term for the imaginary line that divides the body into right and left halves?

The term that refers to the imaginary line that divides the body into right and left halves is the midline. The midline represents the central axis of the body, establishing a point of reference for anatomical locations and directions. When discussing anatomy, the midline is crucial because it helps in identifying the positions of organs and structures relative to one another.

A transversal line would indicate a division of the body into upper and lower parts, while the frontal line divides it into anterior (front) and posterior (back) portions. The sagittal plane moves parallel to the midline but does not specifically refer to the dividing line itself; it encompasses any vertical plane that divides the body into right and left sections. Therefore, midline is the most precise term for the line that directly serves the purpose of splitting the body into right and left halves.