The name comes directly from the Estonian word meaning “dawn.” Its masculine form is Koidu. The designated name day in Estonia is July 7. The name is borne by famous Estonian poet Lydia Koidula (1843-1886). Lydia Koidula meaning “Lydia of the Dawn” was the pen name for Lydia Emilie Florentine Janssen. The epithet caught on after writer Carl Robert Jakobson gave it to her. She is also known as Koidulaulik meaning “Singer of the Dawn.”She was one of the first authors to write in Estonian and is known as the foundress of the Estonian theatre.