from
The Collaborative International Dictionary of English v.0.48
Dovetail \Dove"tail`\, n. (Carp.)
A flaring tenon, or tongue (shaped like a bird's tail
spread), and a mortise, or socket, into which it fits
tightly, making an interlocking joint between two pieces
which resists pulling a part in all directions except one.
[1913 Webster]
{Dovetail molding} (Arch.), a molding of any convex section
arranged in a sort of zigzag, like a series of dovetails.
{Dovetail saw} (Carp.), a saw used in dovetailing.
[1913 Webster]