The American Heritage® Dictionary of the English Language, 4th Edition
n. A small electronic device containing a semiconductor and having at least three electrical contacts, used in a circuit as an amplifier, detector, or switch.
n. a solid-state semiconductor device, with three terminals, which can be used for amplification, switching, voltage stabilization, signal modulation, and many other functions
n. a transistor radio
the GNU version of the Collaborative International Dictionary of English
n. a component used in electronic devices consisting of three regions of at least two types of a semiconducting material, such as doped silicon, connected to each other and to three electrodes in a conducting path so as to modify the current or voltage in an electronic circuit.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. a semiconductor device capable of amplification
Word Usage
"As their colleagues watched with a mix of wonder and envy, they showed how their gizmo, which was dubbed a transistor, could take an electric current, amplify it, and switch it on and off."