(chemistry) A specific arrangement of atoms that repeats within a macromolecule / (genetics) A specific sequence of bases that repeats within a nucleic acid (or of amino acids within a protein)

(anatomy) The structure consisting of hair, hair follicle, arrector pili muscle and sebaceous gland.

plural of astronomical unit

(geometry) A circle of radius 1. / (trigonometry, the unit circle) The circle of radius 1 with centre at the origin, used in defining trigonometric functions.

plural of unit of measure

plural of base unit

A unit of measurement which is not itself defined in terms of other units, and from which other units may be derived. / The main unit of a computer or hi-fi system.

Any simple step in a multi-step chemical engineering process; examples include distillation, evaporation, mixing, filtration, crystallization etc.

(mathematics) A vector with the length of 1.

plural of unit vector