A more thorough explanation:

Reasonable notice is a legal notification that is required by law or agreement. It is a definite legal cognizance, actual or constructive, of an existing right or title. A person has notice of a fact or condition if that person has actual knowledge of it, has received information about it, has reason to know about it, knows about a related fact, or is considered as having been able to ascertain it by checking an official filing or recording.

• If you are renting a house and want to move out, you must give your landlord written notice 30 days before vacating the premises. This is an example of reasonable notice.
• If a person buys a property with a registered deed, they are presumed to have constructive notice of the contents of the deed. This is an example of constructive notice.
• If a company wants to trademark their logo, they must use the symbol with the letter R (®) or “Reg. U.S. Pat. & Tm. Off.” to give notice of their exclusive rights. This is an example of notice in intellectual property law.

These examples illustrate how reasonable notice is given in different situations and how it is important to follow the legal requirements for giving notice.