hemlock

n. poisonous plant used as strong sedative

The word hemlock has two commonly understood meanings, and may also refer to a number of other things:Conium, or more specifically, Conium maculatum, a common European herb that contains the alkaloid coniine and was probably the state poison of Ancient Greece, and the purported poison used in the execution of Socrates (This is the more commonly understood meaning in a European and most historical contexts.)Tsuga, a genus of conifers originally named "hemlocks" due to a perceived similarity in the scent of the crushed foliage to that of Conium. This is the more commonly understood meaning in the United States and Canada.
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Noun
1. poisonous drug derived from an Eurasian plant of the genus Conium; "Socrates refused to flee and died by drinking hemlock"
(hypernym) plant toxin, phytotoxin
2. large branching biennial herb native to Eurasia and Africa and adventive in North America having large fernlike leaves and white flowers; usually found in damp habitats; all parts extremely poisonous
(synonym) poison hemlock, poison parsley, California fern, Nebraska fern, winter fern, Conium maculatum
(hypernym) poisonous plant
(member-holonym) Conium, genus Conium
3. soft coarse splintery wood of a hemlock tree especially the western hemlock
(hypernym) wood
(substance-holonym) hemlock tree
4. an evergreen tree
(synonym) hemlock tree
(hypernym) conifer, coniferous tree
(hyponym) eastern hemlock, Canadian hemlock, spruce pine, Tsuga canadensis
(member-holonym) Tsuga, genus Tsuga

(n.)
The wood or timber of the hemlock tree.
  

(n.)
The name of several poisonous umbelliferous herbs having finely cut leaves and small white flowers, as the Cicuta maculata, bulbifera, and virosa, and the Conium maculatum. See Conium.
  

(n.)
An evergreen tree common in North America (Abies, / Tsuga, Canadensis); hemlock spruce.
  

the common ground or dwarf hemlock, a bitter, poisonous plant. The Hebrew rosh is rendered "hemlock" in two passages, (Hosea 10:4; Amos 6:12) but elsewhere "gall." See: Gall (It is possible that the plant is rather the poppy than an hemlock.-Cook.)