Dictionary of Medieval Names
from European Sources

January m. Latin Ianuarius '[month] of Janus', the name of a Roman god.

Italy
Latin
1376 Ianuarii (gen) DouGen1 p. 237, Ianuario (abl) ibid. p. 143; 1522x1532 Ianuarius (nom) DSF p. 57, 15
Spain
Latin
1019 Genoario (abl) CDCB-XV MMCLXXIV, Jenuer (nom) ibid. MMCLXXIV
Cite as: S.L. Uckelman. "January". In S.L. Uckelman, ed. The Dictionary of Medieval Names from European Sources, Edition 2017, no. 1. http://dmnes.org/2017/1/name/January.