Tertia \t(e)-rtia, ter-tia\ as a girl's name is of Latin origin, and the meaning of Tertia is "third". Unusual number name (see Prima and Secunda). Octavia, which means "eighth", is more popular.

Tertia has 3 variant forms: Tercia, Tersia and Tersha.

Baby names that sound like Tertia are Teresia, Darcia, Tricia, Terresia and Trisia.