The name was originally given to children born on Sunday, dies dominica. Later, it was also used as a feminine of Dominic, in honor of the important saint by that name.
Cite as: J. Uckelman, S.L. Uckelman. "Dominica". In S.L. Uckelman, ed. The Dictionary of Medieval Names from European Sources, Edition 2015, no. 2. http://dmnes.org/2015/2/name/Dominica.