Glossary
Waiver
Voluntarily giving up a known right. Waivers can be express (signed in writing) or implied (inferred from conduct). Once you waive a right, you usually can't get it back.
Many legal rights can be waived: the right to a jury trial, the right to object to personal jurisdiction, the right to certain procedural protections. Some can't be waived (subject matter jurisdiction, for example, can never be waived).
In litigation, waiver often happens by silence or delay. If you don't object to something at the right time, you may have waived the right to complain about it. Pro se litigants sometimes wait too long to raise an objection because they didn't know the deadline mattered, only to find the issue is waived forever.