Lewis & Short

1. issus, a, um, adj., a childish form of ipse, used with little children as a term of endearment: ISSA HAVE, Inscr. ap. Fabr. p. 45, n. 255.
Issa, the name of a pet slut, Mart. 1, 109.
Also dim.:issŭlus, a, um, Inscr. ap. Fabr. n. 254.