Invade comes from Latin invādere — 'to go into' — combining in- with vādere meaning 'to go, to rush'. The same root produced evade (to go out) and pervade (to go through).
To enter a country or region so as to subjugate it; to encroach upon or intrude on.
From Latin invādere meaning 'to go into, to fall upon, to attack', from in- 'into' + vādere 'to go, to walk, to rush'. The Latin vādere was a forceful word for movement — not a stroll but a march. Roman military usage gave invādere its hostile edge: to go into enemy territory was to invade it. The same root gives us evade (to go out of, to escape