means A stream is a flowing body of water smaller than a river, or by extension any continuous flow of things — data, light, consciousness, or chatter.

from From Old English 'strēam,' a thoroughly Germanic word with cousins all over the north: Old Norse 'straumr,' Dutch 'stroom,' German 'Strom.' These all trace back to a Proto-Germanic '*straumaz,' and behind that lies a Proto-Indo-European root '*srew-' meaning 'to flow' — the same ancient current that, traveling through Greek, gave us 'rheum' and 'rhythm.' Water has always been the word's first job; the modern senses of streaming data and streaming video are recent borrowings of that same image of something flowing steadily past you.