What is "embushment"

Usage examples of "embushment".

And by the way Sir Meliagrance laid in an embushment the best archers that he might get in his country, to the number of thirty, to await upon Sir Launcelot, charging them that if they saw such a manner of knight come by the way upon a white horse, that in any wise they slay his horse, but in no manner of wise have not ado with him bodily, for he is over-hardy to be overcome.

And so by the advice of Sir Launcelot, they put them all in an embushment in a wood, as nigh Carlisle as they might, and there they abode still, to wit what the king would do.

And when the said knights came into the wood, anon they espied and saw the great embushment, and returned and told Sir Launcelot that there lay in await for them three score thousand Romans.