Gilleon \gi(l)-leon\ as a boy's name is a variant of Gillean (Irish, Gaelic), and the meaning of Gilleon is "servant of Saint John".
The baby name Gilleon sounds like Gillon, Gillion and Gillen. Other similar baby names are Gillson, Dillon, Dillen, Gaillen, Gilson, Gideon, Gilles, Gilley, Gillian, Gillan, Gilean, Gillett, Gillman, Gilon, Gillroy, Killean and Millen.