How can we differentiate spotting, vaginal bleeding and a period?

Symantics: The definitions I use with my patients: spotting is when you only need one pad or tampon in 24 hours to contain the blood. Bleeding is when you need more than one pad or tampon in 24 hours. Period is when you're bleeding during your regular time during the month. (some people have very irregular bleeding and so they can't really call it their period.) hope this helps.