Definition of intrusion

The word "intrusion" originated in the Middle English period, around the 14th century, from the Old French word "intrusion" which meant "an intervention in a lawsuit" or "an action created by that intervention". In its original sense, "intrusion" referred to an unwelcome act of interference in legal proceedings, often by a third party seeking to assert their own rights or interests. Over time, the meaning of "intrusion" evolved to describe any unwelcome or forceful entry, particularly into private property or restricted areas, where it took on the meaning of a "penetration" or "incursion" that was not warranted or authorized. Today, "intrusion" is commonly used in various contexts, such as to describe the act of a computer hacker gaining unauthorized access to a computer system or network, or a student trespassing into a restricted area of a school campus. The etymology of "intrusion" serves as a reminder of its root meaning as an unwelcome, uninvited, and unwarranted invasion or interference, whether in legal disputes or more contemporary contexts involving technology or access to restricted areas.