Lewis Short
(adverb) : singultim. from singultus; cf.: furtim, partim, etc.
* Sobbingly: μετά λυγμοῦ, Hor. S. 1, 6, 56 (others less correctly make it = singulatim, singillatim, singly): lamentabiles questus singultim instrepebat,App. M p. 127, 36.
Charlton T. Lewis, Charles Short, A Latin Dictionary