The answer is a midsagittal plane.
Midsaggital plane refers to the hypothetical plane, which dissects the body into two equal halves along a vertical axis, that is, the right half and the left half. The midsagittal is an even plane of the body. It is witnessed in species with bilateral symmetry, like humans.
The midsaggital plane is also known as the median plane or the midline of a species. The median or the midsagittal plane passes through the midline compositions, like the navel and the spinal cord. It is primarily used to illustrate the position of an organ in the body.