(Rubik's Cube) A method of solving the Rubik's Cube in which one starts with a cross, then finishes the F2L, then does OLL and PLL.

An instrument for locating rebars and measuring the depth of concrete that covers them.

rare earth element

(chemistry, obsolete) Any of the four metals aluminum, gallium, indium and thallium of the boron group in the periodic table of elements.

An abrasive, distorted subgenre of heavy metal music influenced by hardcore punk and doom metal.

(mathematics, numerical analysis) One of the Runge-Kutta methods for solving ordinary differential equations.

(mathematics, numerical analysis) Any of an important family of implicit and explicit iterative methods for the approximation of solutions of ordinary differential equations.

(mathematics, numerical analysis) A method for solving ordinary differential equations, using six function evaluations to calculate fourth- and fifth-order accurate solutions, the difference between which is then taken to be the error of the (fourth-order) solution.

Alternative spelling of attometre

An instrument sensitive to ionizing radiations used in prospecting for radioactive deposits.