From The Collaborative International Dictionary of English v.0.48 [gcide]:
Armature \Ar"ma*ture\, n. [L. armatura, fr. armare to arm: cf.
F. armature. See Arm, v. t., Armor.]
1. Armor; whatever is worn or used for the protection and
defense of the body, esp. the protective outfit of some
animals and plants.
[1913 Webster]
2. (Magnetism) A piece of soft iron used to connect the two
poles of a magnet, or electro-magnet, in order to complete
the circuit, or to receive and apply the magnetic force.
In the ordinary horseshoe magnet, it serves to prevent the
dissipation of the magnetic force.
[1913 Webster]
3. (Arch.) Iron bars or framing employed for the
consolidation of a building, as in sustaining slender
columns, holding up canopies, etc. --Oxf. Gloss.
[1913 Webster]
4. (Elec.) That moving part of a dynamo or electric generator
in which a current is induced by a moving through a
magnetic field, or, in an electric motor, the part through
which the applied current moves, thereby generating
torque. The armature usually consists of a series of coils
or groups of insulated conductors surrounding a core of
iron.
[Webster 1913 Suppl.]
From WordNet (r) 3.0 (2006) [wn]:
armature
n 1: coil in which voltage is induced by motion through a
magnetic field