Hypertext Webster Gateway: "conchoidal"
From Webster's Revised Unabridged Dictionary (1913) (web1913)
Conchoidal \Con*choid"al\, a. [Cf. F. concho["i]dal.] (Min.)
Having elevations or depressions in form like one half of a
bivalve shell; -- applied principally to a surface produced
by fracture.
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