What are ovas?

Some articles on ovas, ova:

Switch (manga) - Media - OVAs
... The casts in the OVA is the following Character Cast Eto Kai Jun Fukuyama Kurabayashi Hal Sakurai Takahiro Hiki Masataka Junichi Suwabe Masami Ibu Hiroki Touchi ...
Machine Robo: Revenge Of Cronos - Characters - Guest Characters
... Reincarnated in the OVAs as Nami Kojima ... Reincarnated in the OVAs as Kyoko Yoshida ... Her OVA incarnation is Yuko Sato ...
Tsubasa: Reservoir Chronicle - Reception - Anime Reception
... Although the Tsubasa OVAs were not the first original animation DVDs (OADs), OVAs published with manga volumes, its release helped to popularize the term ... Chris Beveridge from Mania Entertainment considered the OVAs to have better quality than the TV series, mainly because they were developed by Production I.G instead of Bee Train and because they have a darker ... In a further review, Beveridge found fascinating the events occurring in the OVAs due to its the number of revelations changed the way people viewed the series ...