OAVs

From OMGWiki

The five-episode OAV series is the first exposure to Oh My Goddess! many non-Japanese anime fans ever had. It attempts to follow the story of the manga, but, being condensed into a few episodes, it is highly abridged.

For those unfamiliar with the term, OVA means Original Video Animation (OAV means Original Animation Video... both terms are the same thing), and can be compared to... oh, say, straight-to-home-video release. The difference is that western (i.e. Hollywood) straight-to-video's are usually produced with notably lesser quality than moviegoing releases, and thus carry a negative connotation. OVAs are produced with greater budget than TV series, and as such the quality is usually very good. So, OVAs in Japan does not carry the stigma of straight-to-vide in the West.

The Oh My Goddess OVA was created in the early to mid nineties (they made each episode one at a time).