DEFINITION of 'X-Mark Signature'
An X-mark made by a person in lieu of a signature. Due to illiteracy or disability, a person may be unable to append a full signature to a document as attestation that he or she has reviewed and approved its contents. In order to be legally valid, the X-mark signature must be witnessed.
BREAKING DOWN 'X-Mark Signature'
Due to the obvious potential for fraud, doubts may arise about the validity and enforceability of documents signed with X-mark signatures. In some U.S. states, for example, the law requires courts to invalidate wills signed with an X unless the testator was physically or mentally incapable of signing his or her full name.