The term OVA, or Original Video Animation, refers to a specific direct-to-video format of Japanese animation. The anime industry uses the term interchangeably with OAV, or Original Animated Video, according to the Anime News Network.
An OVA does not receive a television broadcast as a made-for-TV anime series does. Nor does it get distributed to movie theaters. Most “adult” animation productions in Japan go directly to the home video market as OAVs since they could not receive television broadcasts or mainstream film distribution.
OVAs do not face the same budget or time crunches that anime TV series do. The extra time and money at the producers' disposal generally result in higher production values and more detailed workmanship than televisions anime can offer, according to the Anime News Network.
Unlike anime TV series, which often adhere closely to an original manga, or printed comic, OVAs generally feature scripts based on original stories. In some cases, however, an OVA series will base itself on a pre-existing manga or anime TV series, simply offering new stories using the established premise and characters.