To be pedantic you mean "seit" (since/until), not "seid" as in "ihr seit laut" (you [plural] are loud).
- „ihr seid laut“: you are loud (seid is the second person plural form of to be)
- „seit drei Stunden“: for three hours (seit gives a temporal reference)
- „bis am Freitag“: by friday (in the context of homework)
- „der Biss“: the bite