Anime which have episodes of or more 15 minutes in length and broadcast on television.
Anime which are under 15 minutes in length and broadcast on television.
Anime that have originally been released at theaters.
Specials that have been included in DVD/Blu-ray releases, picture dramas, pilots, etc.
OVA (Original Video Animation)
Anime that have been released directly on DVD/Blu-ray without originally going through a theatrical release or television broadcast.
ONA (Original Net Animation)
Anime that have been originally released online or are only available through streaming services.