What is the medical term for bilateral?

Both sides

To expand a bit on the above answer, bilateral, in this case, refers to something that occurs in both the left and right sides of the body (such as paralysis of both legs), or occurs in both of a pair of organs such as an infection in both lungs simultaneously.

In general, bilateral means ocurring on both sides of a line of symmetry, whether real or imagined. The human body exhibits bilateral symmetry in that the right half is similar in appearance and function to the left half.