Endless means having no end or finish, continuing forever or seeming to go on forever. When you're on a long car trip and keep asking “Are we there yet?” the ride might feel endless, even though you know it will eventually end. An endless ocean stretches to the horizon with no land in sight. An endless loop in a computer program keeps repeating the same instructions over and over without stopping.

The word can describe actual infinity, like the endless expanse of space, or it can describe something that just feels like it will never end. When a teacher gives an endless lecture, it's not truly infinite, but it certainly feels that way when you're watching the clock. A creative person might have endless ideas, meaning new ones keep flowing without stopping. Endless summer describes those perfect vacation weeks that seem to last forever in memory.

Sometimes people use endless to emphasize abundance: endless possibilities, endless opportunities, or endless energy. When something is described as endless, it suggests more than you could ever use up or experience completely.