How much is a stack of $1?

I'm curious, how much exactly is a stack of $1 bills worth? Is it a significant amount of money, or just a small pile? And if I were to have a stack of $1 bills in front of me, would it be a manageable size or would it take up a lot of space? Additionally, is there a standard definition for what constitutes a "stack" of bills, or does it vary depending on the context? I'm just trying to get a better understanding of the term and its financial implications.