isotope

noun

iso·​tope ˈī-sə-ˌtōp 

1

: any of two or more species of atoms of a chemical element with the same atomic number and nearly identical chemical behavior but with differing atomic mass or mass number and different physical properties

2

: nuclide

isotopic

ˌī-sə-ˈtä-pik  -ˈtō- 

adjective

isotopically

ˌī-sə-ˈtä-pi-k(ə-)lē  -ˈtō- 

adverb

Examples of isotope in a Sentence

Recent Examples on the Web

Nitrogen has two stable isotopes: nitrogen-14, the more abundant form, and nitrogen-15, the heavier, less common form. —Melanie Beasley, The Conversation, 25 July 2025

Study participants were given a special water to drink that contained isotopes that came out in their urine. —Maria Godoy, NPR, 24 July 2025

Molten salt will contain the isotopes to reduce risks associated with remaining radioactivity. —IEEE Spectrum, 7 July 2025

As these glom on, the nucleus becomes an unstable version of itself — a radioactive isotope. —Jenna Ahart, Quanta Magazine, 2 July 2025

Word History

Etymology

is- + Greek topos place

First Known Use

1913, in the meaning defined at sense 1

Rhymes for isotope

• antelope
• bronchoscope
• cantaloupe
• cystoscope
• endoscope
• envelope
• epitope
• gyroscope
• horoscope
• microscope
• misanthrope
• pericope

Kids Definition

isotope

noun

iso·​tope ˈī-sə-ˌtōp 

: any of the forms of an element that differ in the number of neutrons in an atom

isotopic

ˌī-sə-ˈtäp-ik 

-ˈtō-pik

adjective

isotopically

-ˈtäp-i-k(ə-)lē 

-ˈtō-pi-

adverb

Medical Definition

isotope

noun

iso·​tope ˈī-sə-ˌtōp 

1

: any of two or more species of atoms of a chemical element with the same atomic number and position in the periodic table and nearly identical chemical behavior but with differing atomic mass or mass number and different physical properties

2

: nuclide

isotopic

ˌī-sə-ˈtäp-ik  -ˈtō-pik 

adjective

isotopically

-ˈtäp-i-k(ə-)lē  -ˈtō-pi- 

adverb

isotopy

ˈī-sə-ˌtō-pē  ī-ˈsät-ə-pē 

noun

plural isotopies