X is a mark that usually serves as the signature of a person who is physically handicapped or illiterate. The signer’s name appears near the mark. If the mark is to be notarized as a signature, in addition to the notary public two signing witnesses are also required.
X denotes a symbol equivalent to “by” when used in giving dimensions, as in 2 x 7inches. It can also be a mark on a document like an application form which indicates a selection, such as “yes” or “no” especially a mark on a ballot to indicate a vote. It is also used to denote any unknown, unspecified, or variable factor, number, person, or thing.
X is also used as abbreviation of ‘Ex’ used in Ex wife, Ex warrants, Ex dividend.