The American Heritage® Dictionary of the English Language, 4th Edition
n. A particle, such as an electron, proton, or neutron, having half-integral spin and obeying statistical rules requiring that not more than one in a set of identical particles may occupy a particular quantum state.
n. A particle with totally antisymmetric composite quantum states, which means it must obey the Pauli exclusion principle and Fermi-Dirac statistics. They have half-integer spin. Among them are many elementary particles, most derived from quarks. Compare boson.
the GNU version of the Collaborative International Dictionary of English
n. any particle that obeys Fermi-Dirac statistcs and is subject to the Pauli exclusion principle.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. any particle that obeys Fermi-Dirac statistics and is subject to the Pauli exclusion principle
Word Usage
"At low energies the Higgs gets a vacuum expectation value, and acts like a mass term, converting the left-handed fermion into a right-handed fermion, which is what you want."