The word ‘galaxy’ is derived from a Greek word for ‘milk’. Although there is not absolute proof as to why they named our galaxy as something related to milk, some researchers believe what seems to be the most likely and also most plausible reason for the name – its appearance against the night sky.
The milky band that you see on the edge of the Milky Way is actually a concentrated chunk of millions upon millions of stars that shine incredibly brightly. Also, the image of the Milky Way that we see up in the night sky in unpolluted areas (especially remote, rural locations) is on its side; it is due to the angle of viewing that the galaxy appears to be a thin, shiny arc of light, rather than an enormous, bright disk.
Picture Credit : Google