What is the meaning of a single star?

Answer 1

The whole of the universe is made up of single stars, so your question is not that clear.

You may be referring to the first start you see at dusk, which is probably Venus, which is in fact a planet. You may even see Sirius, the bright star in Canis Major. To see just a single star has no specific meaning unless you want to put a meaning to it youself, in that case you have all the meanings in the world to choose from.