deviation. 1  the act of deviating. 2  departure from a standard or norm. 3  Statistics. the difference between one of a set of values and some fixed value, usually the mean of the set. 4  Navigation. the error of a magnetic compass, as that of a ship, on a given heading as a result of local magnetism. 5  Optics.
The definition of an invitation is a request for a person's attendance at an event. An example of an invitation is a printed card asking family and friends to come to the sender's wedding. 1  an inviting to come somewhere or do something. 2  the message or note used in inviting.  enticement or allurement.
Wojciech Burda/iStock/Getty Images. When you receive an invitation -- either verbally or via your inbox, mailbox or voicemail -- respond promptly. Whether your answer is yay or nay, it's inconsiderate to let the invitation simmer.eep It Short. When you say no, there's no need to explain why, states Elizabeth Howell of the Emily Post Institute. In fact, Howell claims it is rude for a host to push for an explanation.