abatis
Concise Oxford English Dictionary © 2008 Oxford University Press:
abatis /ˈabətɪs/ (also abattis)
▶noun (pl. same, abatises, or abattises) historical a defence made of felled trees placed together with the boughs pointing outwards.
– origin C18: from Fr., lit. ‘felled (trees)’, from OFr. abatre ‘to fell’.
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