Infinity means endlessness, a quantity or expanse that goes on forever without stopping. If you started counting numbers and never stopped, you'd be counting toward infinity. No matter how high you count (a million, a billion, a trillion), there's always another number after it. That's infinity: something with no final point, no edge, no conclusion.

You can't actually reach infinity or hold it in your hand. It's more of an idea than something real you can touch. Mathematicians use the symbol ∞ (which looks like a sideways 8) to represent infinity in their work. They study infinite sets of numbers and infinite patterns that help solve complicated problems.

Space might extend infinitely in all directions, or it might not. Scientists still debate this question. Time might stretch infinitely into the future, continuing forever and ever. Even smaller things can have infinity hiding inside them: if you tried to list all the numbers between 1 and 2 (like 1.1, 1.01, 1.001, 1.0001), you'd find infinitely many. Between any two numbers, no matter how close together, mathematicians have proven there are infinitely many numbers waiting to be discovered.

The word also describes things that merely feel endless, like when you're waiting for something exciting and the minutes seem to stretch out infinitely.