"Lateral support" refers to the help or assistance provided from the sides or sideways. It means having someone or something to rely on or lean on for support, guidance, or stability in a horizontal or sideways direction. Full definition
The interior are dressed in leather and the seats are soft and comfortable with good lateral support for the front seats as well. (carwale.com)
They offer particularly good lateral support for such minimal weight. (porsche.com)
The leather - covered power front seats are wide enough for comfort, although we found that they left something to be desired in terms of lateral support for hard cornering. (cnet.com)