'countersignature' definitions:

Definition of 'countersignature'

From: WordNet
noun
A second confirming signature endorsing a document already signed [syn: countersignature, countersign]

Definition of 'countersignature'

From: GCIDE
  • countersignature \countersignature\ n. a second confirming signature endorsing a document already signed.
  • Syn: countersign. [WordNet 1.5]