Death's-herb (n.)
definition: The deadly nightshade (Atropa belladonna).

Death's-herb is a 12 letter word that begins with a D and ends in a B

Lady's thumb
definition: An annual weed (Polygonum Persicaria)
Having a lanceolate leaf with a dark spot in the middle.
Lady's thumb is a 12 letter word that begins with an L and ends in a B

Microcoulomb (n.)
definition: A measure of electrical quantity; the millionth part of one coulomb.

Microcoulomb is a 12 letter word that begins with an M and ends in a B

Spider's web
definition: The silken web which is formed by most kinds of spiders
Particularly the web spun to entrap their prey. See Geometric spider Triangle spider under Geometric and Triangle.
Spider's web is a 12 letter word that begins with an S and ends in a B

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