What is the X in X-mas?
1879, from French limbique (1878, Broca), from limbe, from Latin limbus "edge" (see limb (n.2)). Limbic system is attested from 1950.
limbic lim·bic (lĭm'bĭk)adj.
Of, relating to, or characterized by a limbus.
Of or relating to the limbic system.