* No Central Database: There's no single, definitive database that tracks every anime series ever made. Many are produced independently, and some may not even be officially released or widely distributed.
* Definition of "Series": What counts as a series? Is it only TV series? Do movies, OVAs, or even one-off specials count? The definition can be subjective.
* New Series Constantly: Anime is a constantly evolving industry, with new series being produced all the time.
However, you can find estimates:
* MyAnimeList: A popular anime database, MyAnimeList lists thousands of anime series and has a significant number of entries.
* Anime News Network (ANN): ANN is a well-respected news and information site about anime. It has a large database of anime entries.
Ultimately, it's safe to say there are thousands, even tens of thousands, of anime series out there.