'in-stream' is a compound word formed from the preposition 'in' and the noun 'stream', where 'in' means 'inside' and 'stream' refers to a continuous flow, especially of water or data.

The term 'in-stream' was coined in modern English to describe things that occur within a stream, especially in the context of digital media and advertising.

Initially, it referred to something physically inside a stream of water, but now it is commonly used for digital content that appears within a media stream.