Etymology
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incursion (n.)
"hostile attack," early 15c., from Old French incursion "invasion, attack, assault" (14c.) or directly from Latin incursionem (nominative incursio) "a running against, hostile attack," noun of action from past participle stem of incurrere "run into or against, rush at" (see incur).
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raider (n.)

"one engaged in a hostile or predatory incursion," 1863, agent noun from raid (v.). A word from the American Civil War.

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inroad (n.)
1540s, "hostile incursion, raid, foray," from in- (2) "in;" second element is road (n.) in the obsolete sense of "riding;" related to raid (v.). Related: Inroads.
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foray (n.)
late 14c., "predatory incursion," Scottish, from the verb (14c.), perhaps a back-formation of Middle English forreyer "raider, forager" (mid-14c.), from Old French forrier, from forrer "to forage," from forrage "fodder; foraging; pillaging, looting" (see forage (n.)). Disused by 18c.; revived by Scott. As a verb from 14c.
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raid (n.)

early 15c., "mounted military expedition," Scottish and northern English form of rade "a riding, journey," from Old English rad "a riding, ride, expedition, journey; raid," (see road). The word fell into obscurity by 17c., but it was revived by Scott ("The Lay of the Last Minstrel," 1805; "Rob Roy," 1818), with a more extended sense of "attack, foray, hostile or predatory incursion." By 1873 of any sudden or vigorous descent (police raids, etc.). Of air raids by 1908.

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invasion (n.)
Origin and meaning of invasion

mid-15c., invasioun, "an assault, attack, act of entering a country or territory as an enemy," from Old French invasion "invasion, attack, assault" (12c.), from Late Latin invasionem (nominative invasio) "an attack, invasion," noun of action from past-participle stem of Latin invadere "to go, come, or get into; enter violently, penetrate into as an enemy, assail, assault, make an attack on," from in- "in" (from PIE root *en "in") + vadere "to go, to walk, go hastily," from PIE root *wadh- (2) "to go" (source also of Old English wadan "to go," Latin vadum "ford;" see wade (v.)).

In extended sense, of diseases, "a harmful incursion of any kind;" with reference to rights, etc., "infringement by intrusion, encroachment by entering into or taking away what belongs to another."

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road (n.)

Middle English rode, from Old English rad "riding expedition, journey, hostile incursion," from Proto-Germanic *raido (source also of Old Frisian red "ride," Old Saxon reda, Middle Dutch rede, Old High German reita "foray, raid"), from PIE *reidh- "to ride" (see ride (v.)). Also related to raid (n.).

In Middle English it was still, "a riding, a journey on horseback; a mounted raid;" the sense of "an open passage or way for traveling between two places" is recorded from 1590s, and the older senses now are obsolete. "The late appearance of this sense makes its development from sense 1 somewhat obscure," according to OED, which however finds similar evolutions in Flemish and Frisian words. The modern spelling was established 18c.  

The meaning "narrow stretch of sheltered water near shore where ships can lie at anchor" is from early 14c. (as in Virginia's Hampton Roads). In late 19c. U.S. use it is often short for railroad.

On the road "traveling" is from 1640s. Road test (n.) of a vehicle's performance is by 1906; as a verb from 1937. Road hog "one who is objectionable on the road" [OED] is attested from 1886; road rage is by 1988. Road map is from 1786; road trip is by 1950, originally of baseball teams. Old English had radwerig "weary of traveling."

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