Estoppel by acquiescence

The common law doctrine of estoppel by acquiescence is applied when one party gives legal notice to a second party of a fact or claim, and the second party fails to challenge or refute that claim within a reasonable time. The second party is said to have acquiesced to the claim, and is estopped from later challenging it, or making a counterclaim. The doctrine is similar to, and often applied with, estoppel by laches.