strange quark

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

• noun The flavor of quark that has a charge of − ¹/₃ , a mass about 190 times that of an electron, a strangeness of −1, and that 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 -1/3 and a mass about 80 to 130 MeV. Symbol: s

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

• noun a quark with an electric charge of -1/3 and a mass 988 times that of an electron and a strangeness of -1