The planes of the body are one of the first topics in Anatomy and Physiology. The concept relies on understanding the orientation of the specimen.
Sagittal = cuts the body into a left and right side (red)
Coronal = cuts the body into a front and back half (blue)
Transverse = cuts the body into a top and a bottom (green)
Also, check out this clip from “The Dome” which shows a cow being cut in half along its sagittal plane.