To flow in a continuous current, like a river or a video that plays without needing to download it first.
When something is streamed, it is usually happening right now and you can watch or listen to it as it happens.
Examples:
The water streamed down the mountain.
I streamed a movie on my computer.
The music streamed from the speakers.
The ants streamed out of the anthill.
The colors streamed across the sky like a rainbow.
The tears streamed down her face.