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periodic table

periodic table

noun

a table illustrating the periodic system, in which the chemical elements, formerly arranged in the order of their atomic weights and now according to their atomic numbers, are shown in related groups.
Periodic Table

Periodic Table

A table in which the chemical elements are arranged in order of increasing atomic number. Elements with similar properties are arranged in the same column (called a group), and elements with the same number of electron shells are arranged in the same row (called a period).

Synonyms

periodic table

American

[peer-ee-od-ik, peer-] / ˈpɪər iˈɒd ɪk, ˌpɪər- /

noun

Chemistry.

a table illustrating the periodic system, in which the chemical elements, formerly arranged in the order of their atomic weights and now according to their atomic numbers, are shown in related groups.

periodic table British

/ ˌpɪərɪˈɒdɪk /

noun

a table of the elements, arranged in order of increasing atomic number, based on the periodic law. Elements having similar chemical properties and electronic structures appear in vertical columns (groups)

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Periodic Table Scientific

A table in which the chemical elements are arranged in order of increasing atomic number. Elements with similar properties are arranged in the same column (called a group), and elements with the same number of electron shells are arranged in the same row (called a period).

Etymology

Origin of periodic table

First recorded in 1890–95

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

The periodic table supposedly came to Dmitri Mendeleev in a dream.

From The Wall Street Journal • May 13, 2026

Every character has an adorable quirk or two, or at minimum owns a dorky T-shirt with a periodic table joke or a cartoon cat.

From Los Angeles Times • Mar. 18, 2026

With important electrical and magnetic qualities, rare earths consist of 17 elements in the lanthanide group of the periodic table, plus scandium and yytrium.

From BBC • Feb. 5, 2026

These include scandium, yttrium and the lanthanides, which account for 15 chemical elements in the periodic table.

From MarketWatch • Oct. 28, 2025

That day I hurried home and studied my periodic table.

From "Because of Mr. Terupt" by Rob Buyea

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023