Larissa is an English spelling of the Eastern European "Larisa," which means "protection" in both Russian and American contexts, according to the "Baby Names" section of SheKnows.
According to Behind the Name, the name is believed to have its origins in the ancient Greek city of Larisa, which means "citadel." It is also the name of a 4th century Greek martyr-turned-saint and a nymph in Greek mythology. The name spelled Larisa is most popular in Bosnia and Herzogovina, ranking 55th in the nation. Variations of Larisa are found in several languages, including Ukranian, Russian, Dutch, French, German, Italian, Portuguese, Spanish, Hungarian and Slovene.