A legal document called a caveat represents a caution noted on a legal file, litigation or title, warning other of a person's interest in the title or litigation, with the person entering the caveat called the caveator.
Alexander v McKillop & Benjafield 43 SCR 551 (1910), a decision of the Supreme Court of Canada, discussed the effect of a caveat as follows:
"This machinery was designed for the protection of rights, not for the creation of rights.
"A caveat prevents any disposition of his title by the registered proprietor in derogation of the caveator's claim until that claim has been satisfied or disposed of, but the caveator's claim must stand or fall on its own merits.
"If the caveator has no right enforceable against the registered owner which entitled him to restrain the alienation of the owner's title then the caveat itself cannot and does not impose any burden on the registered title."
Or
Stephens v Bannan & Gray 5 WWR 201, that a caveat is:
"... nothing more than a caution and an effective notice of a claim of title grounded upon something else and preventing any change in the rights of the caveator by dealings with the land subsequent to the lodging of the caveat."
In the Province of British Columbia, the Land Title Act, formalizes the process of a caveat by providing that:
"A person, in this Act referred to as the caveator, claiming under an unregistered instrument which is incapable of immediate registration, by operation of law, or otherwise, to be entitled to land the title to which is registered under this Act, may by leave of the registrar, granted on terms, if any, the registrar may consider proper, lodge a caveat with the registrar prohibiting registration of a dealing with the land either absolutely or in the manner or to the extent expressed in the caveat."
See also lis pendens, certificate of pending litigation and caveat emptor.