When does it start streaming?

Disney +, netflix, amazone prime and joyn are considered streaming services. Is it streaming when you watch a series on one of these providers on your cell phone or only when you watch a series of these services on your TV?

Streaming means playing the content over the Internet, so of course streaming is also possible on the mobile phone.

Play content over the Internet no matter what medium is streaming.

Of course also with a cell phone.

The medium doesn't matter. You are playing the content on the internet. Stream