charm quark

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The flavor of quark that has a charge of + ²/₃ , has a mass about 2,450 times that of an electron, and belongs to the second generation of elementary fermions.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A quark having a fractional electric charge of +2/3 and a mass about 1150 to 1350 MeV. Symbol: c

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a quark with an electric charge of +2/3 and a mass 2900 times that of an electron and a charm of +1