(evolutionary biology) The principle of biology that states that populations isolated onto islands may undergo evolution towards dwarfism or gigantism to better conform to available resources

(poker) The rule of multiplying the number of outs by four to discover one's approximate chance to make one's hand on the turn or river. Compare rule of two.

(poker) The rule of multiplying the number of outs by two to discover one's approximate chance to make one's hand on the river.

(cellular automata) A simple cellular automaton, unusual in being Turing-complete, where each cell's value changes depending on its current value and those of two neighbouring cells.

(mathematics) A formula used to find the derivatives of products of two or more functions: (f·g)'=f'·g+f·g',!

(linear algebra) An explicit formula for the solution of a system of linear equations with as many equations as unknowns, valid whenever the system has a unique solution.

(mathematics) The rule that the limit of the ratio of two functions equals the limit of the ratio of their derivatives, usable when the former limit is indeterminate and the latter limit exists.

(phonetics) The rule describing a special case of tone reduction in Bantu languages, where in some contexts the second of two adjacent high tones is lowered.

plural of rule joint

plural of ruling pen