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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).

periodic table

American  

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

noun

Chemistry.

1. 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.

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periodic table British  

/ ˌpɪərɪˈɒdɪk /

noun

1. 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)

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Periodic Table Scientific  

1. 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).

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Etymology

Origin of periodic table

First recorded in 1890–95

Example Sentences

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

It has long held a spot on the periodic table of elements, but has remained under the radar despite its use in military systems, self-driving vehicles and fast chargers for laptops.

From The Wall Street Journal • Feb. 9, 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

Astatine is the rarest naturally occurring element on Earth and among the least explored in the periodic table.

From Science Daily • Nov. 11, 2025

Outsiders might disdain the lab’s focus on radioisotope hunting, but filling in the roster of isotopes throughout the periodic table was important work.

From "Big Science" by Michael Hiltzik