Dictionaries
Article I, Section 9, clause 2
The Privilege of the Writ of Habeas Corpus shall not be suspended unless when in Cases of Rebellion or Invasion the public Safety may require it



A Compendious Dictionary of the English Language (1806)
(Noah Webster 1806)
Invasion     n. hostile entrance, attack, assault



An American Dictionary of the English Language (1828)
www.WebstersDictionary1828.com
(Noah Webster 1828)
Invasion
INVA'SION, noun s as z. [Latin invasio, from invado. See Invade.]

1. A hostile entrance into the possessions of another; particularly, the entrance of a hostile army into a country for the purpose of conquest or plunder, or the attack of a military force. The north of England and south of Scotland were for centuries subject to invasion each from the other. The invasion of England by William the Norman, was in 1066.

2. An attack on the rights of another; infringement or violation.

3. Attack of a disease; as the invasion of the plague, in Egypt.


Merriam-Webster Dictionary (Online)
(Merriam-Webster 2024)