What's the "een" in Halloween?
1570s, from Middle French vaste, from Latin vastus "immense, extensive, huge," also "desolate, unoccupied, empty." The two meanings probably originally attached to two separate words, one with a long -a- one with a short -a-, that merged in early Latin (see waste). Very popular early 18c. as an intensifier. Related: Vastly; vastness.