atom
- 01 B1 Intermediate
the smallest part of a chemical element that can exist.
the basic unit of a chemical element, consisting of a nucleus of protons and neutrons typically surrounded by electrons.
Simple“A water molecule is made of two hydrogen atoms and one oxygen atom.”
In context“The researchers used a scanning tunneling microscope to manipulate individual atoms on the surface of the silicon crystal.”
- 02 C1 Advanced
the smallest possible piece or unit of an idea or a system.
the smallest, indivisible constituent part or unit of a larger conceptual or physical system.
Simple“In this theory, the individual person is the atom of society.”
In context“Logical atomism suggests that the world consists of ultimate facts that cannot be further decomposed into simpler components.”
- 03 C2 Proficiency
a very small amount of something.
an extremely small or negligible quantity of a quality or substance.
Simple“There was not an atom of truth in the rumors spreading through the village.”
In context“He faced the accusations with dignity, showing not an atom of fear even as the verdict was read aloud.”
- 04 C1 Advanced
a single value or symbol that cannot be broken into a list.
a primitive value or a scalar that is not a collection; in some languages, a unique integer representing a string.
Simple“In the Lisp programming language, an atom is a basic element like a number or a symbol.”
In context“The function is designed to process each atom within the nested list structure recursively until it reaches the base case.”
Antonyms
From Middle English attome, from Middle French athome, from Latin atomus (“smallest particle”), from Ancient Greek ἄτομος (átomos, “indivisible”), from ἀ- (a-, “not”) + τέμνω (témnō, “to cut”, o-grade in τομ-) + -ος (-os). Atoms are so named because they were historically thought up as to be the smallest unit of matter, and thus indivisible. Doublet of atomus.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.