Jacey probably evolved as a variant of Josie or as a feminine form of Jason from its pet form Jace. Variant spellings are Jaycee, Jacy, Jaci, Jasy, Jasey and Jasi. (Source: Sheard, K.M., (2011), Llewellyn's Complete Book of Names: For pagans, witches, wiccans, druids, heathens, mages, shamans & independent thinkers of all sorts who are curious about names from every place and time, Llewellyn's Publications, Woodbury, Minnesota, USA, page 195)