In legal theory, all torts are trespasses.
It is, in the common law, the "original" tort as it is most firmly rooted in medieval legal history. As actions for trespass presented increasingly disparate facts to the common law courts, subdivision of the law of torts commenced with trespass being the retained term for torts in regards to another's land.
In law, the term is now usually as regards real property or land only: any unlawful entry upon another's land.
In Point v Dibblee Construction, the Court described trespass as:
"An action for the wrong committed in respect of the plaintiff's land by entry on the same without lawful authority. Trespass constitutes a tort."
But a better definition appears at Harrison v Carswell where Canada's Supreme Court opined (albeit in dissent):
"Trespass in its civil law sense, and in its penal sense too, connotes unjustified invasion of another's possession.
"Where a dwelling house is concerned, the privacy associated with that kind of land-holding makes any unjustified or unprivileged entry a trespass, technically so even if no damage occurs.
"A court however would be likely to award only nominal damages for mere unprivileged entry upon another's private premises where no injury occurs, and it is probable that the plaintiff would be ordered to pay costs for seeking empty vindication. If the trespasser refuses to leave when ordered, he could be forcibly removed but, more likely, the police would be called and the issue would be resolved at that point, or a basis for an action or for a penal charge would arise.
"In short, apart from privileged entry, ... there is a significant element of protection of privacy in resort to trespass to exclude or remove persons from private dwellings."
See also Semayne's Case.
REFERENCES:
- Baker, J., An Introduction to English Legal History (England: Butterworths-Lexis-Nexis, 2002), 4th Edition.
- Harrison v Carswell SCR 200 (1976)
- Point v Dibblee Construction 2 DLR 785 (Ontario, 1934)