quark

noun

1. (particle)In the Standard Model, one of a number of elementary subatomic particles having fractional electric charge that forms matter. They are theorized not to exist in isolation, but only in combinations in hadrons such as neutrons and protons or in quark–gluon plasmas.

   “A simpler and more elegant scheme can be constructed if we allow non-integral values for the charges. We can dispense entirely with the basic baryon b if we assign to the triplet t the following properties: spin #92;frac#123;1#125;#123;2#125;, z#61;#123;-#92;frac#123;1#125;#123;3”

2. (broadly)An integer that uniquely identifies a text string.

   “Two functions are provided to convert between strings and quarks: XrmStringToQuark and XrmQuarkToString […] The second takes a quark as its parameter and returns a pointer to its associated string; it is used primarily for debugging and runtime error messages.”

3. (broadly, slang)A nonsense, trivial text string.
4. (uncountable)A soft, creamy, unripened cheese made from cow's milk, originating from and eaten throughout central, northern, eastern, and southeastern Europe, as well as the Low Countries.
5. (informal)The black-crowned night heron (Nycticorax nycticorax).