Where is tau found?

Excuse me, could you elaborate on where tau is commonly found? I'm curious to understand the context in which it arises and what domains it's particularly relevant to. Is it a mathematical constant that we encounter in everyday life, or is it more specific to certain areas of science and engineering? Additionally, if there are any real-world applications of tau that you could share, that would be incredibly insightful. Thank you for your time and expertise on this matter.