Its source is Christina, an English name meaning "Christ's follower."
This girl's name is used in Finnish.
Other names for which Tina serves as a nickname include Bettina, Martina and Augustina. It began to appear as an independent name at the beginning of the 20th century, reaching its peak in the 1960s.
Tina is essentially an ornament, with no intrinsic meaning. Other such ornaments that have developed into independent names include Nita (from Anita and others) and Rita (from Margarita).