Perhaps some may feel this is a question that is fairly obvious to differentiate. But, still, several people seem to ask this question so that makes it worth addressing. First off, no, lanterns and flashlights are not the same things and if you ever have any issues differentiating between the two of them, this is when you know it is a lantern.
Instead of being tube-shaped, a lantern has a handle and is primarily designed to stand up on its own. Also, it has a much larger head and reflector than any flashlight on the market has. Lastly, a lantern is typically powered by four D cell batteries and a LED flashlight should require nowhere near that amount or size of the battery. At the end of the day, they are not too hard to distinguish so do not worry too much about this.