atom🔊

(chemistry, physics) The smallest possible amount of matter which still retains its identity as a chemical element, now known to consist of a nucleus surrounded by electrons.

(history of science) A hypothetical particle posited by Greek philosophers as an ultimate and indivisible component of matter.

(now generally regarded figuratively) The smallest, indivisible constituent part or unit of something.

(philosophy) In logical atomism, a fundamental fact that cannot be further broken down.

(historical) The smallest medieval unit of time, equal to fifteen ninety-fourths of a second.

A mote of dust in a sunbeam.

A very small amount; a whit.

(computing, programming, Lisp) An individual number or symbol, as opposed to a list; a scalar value.

(mathematics) A non-zero member of a partially ordered set that has only zero below it (assuming that the poset has a least element, its "zero").

(mathematics, set theory) An element of a set that is not itself a set; an urelement.

(Canada) An age group division in hockey for nine- to eleven-year-olds.