atom

IPA: ˈætʌm

(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, usually attributive) An age group division in hockey for nine- to eleven-year-olds.
a Meitei surname from Manipuri

Examples of "atom" in Sentences

An atom is the smallest unit of matter that retains the properties of an element
The nucleus of an atom contains the protons and neutrons, while the electrons orbit around it
Atoms combine to form molecules, which make up the substances we see and interact with every day
The number of protons in an atom's nucleus determines its chemical properties and its place in the periodic table
When atoms gain or lose electrons, they form ions, which can then interact with other atoms to create new compounds