Infinity is defined as A NUMBER bigger than you are able to measure. Most people casually assume a much sloppier meaning, “unlimited”. That is not a problem since the meaning is usually determined by context.
Example: If you look at something from two positions it appears to shift by some angle depending on how far away it is and the length of your baseline. If you look from opposite sides of the Earth’s orbit, that is the longest baseline we have, and accurate measurements can be made out to about 3200 light years. Beyond that we are guessing. Highly scientific guessing, but guessing all the same. That is why when you try to look up the biggest stars, the figures get very uncertain beyond 3200 light years. That is “infinity”.