Akademik

casing nail
noun
: a wire nail that has a small slightly flared head and is used for finish work

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a nail having a small, conical head, slenderer than a common nail of the same length, used for laying floors, fastening matchboarding, and other work in which the head may remain visible. Cf. finishing nail.

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casing nail,
a nail having a flaring head designed to lie flush with the surface into which the nail is driven.

Useful english dictionary. 2012.