noun Uncommon

isotope

EYE-suh-tohp

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Isotope (noun) means one of two or more versions of a chemical element that have the same number of protons but a different number of neutrons. Example: “Carbon-14 is a radioactive isotope used to date ancient bones.”

noun

One of two or more versions of a chemical element that have the same number of protons but a different number of neutrons.

"Carbon-14 is a radioactive isotope used to date ancient bones."

"Uranium has several isotopes, some far more unstable than others."

How to use isotope

Learner’s notes

In plain EnglishA variant of a chemical element that has extra or fewer neutrons in its atoms, but the same number of protons.

Common pairings

radioactive isotope stable isotope

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C2 · Advanced serendipity Fortunate discoveries made entirely by accident.

Gen Z slang rizz Charm — the ability to attract a romantic interest.

B2 · Intermediate empathy The capacity to share another person’s feelings.

C1 · Advanced nonchalant Casually calm and relaxed; unconcerned.

Internet slang delulu Delusional — believing something against the odds.

Etymology nostalgia Greek nostos “return home” + algos “pain”.

C2 · Advanced serendipity Fortunate discoveries made entirely by accident.

Gen Z slang rizz Charm — the ability to attract a romantic interest.

B2 · Intermediate empathy The capacity to share another person’s feelings.

C1 · Advanced nonchalant Casually calm and relaxed; unconcerned.

Internet slang delulu Delusional — believing something against the odds.

Etymology nostalgia Greek nostos “return home” + algos “pain”.

Word forms

Plural: isotopes
Third person singular: isotopes
Past tense: isotoped

Test yourself on “isotope” A quick quiz — meaning, synonyms & usage →

Fill the gap

Can you complete this real example?

Carbon-14 is a radioactive _____ used to date ancient bones.

Etymology

From Greek iso- ("same") plus -tope ("place"), because isotopes occupy the same position in the periodic table. Coined in 1913 by chemist Frederick Soddy, building on a suggestion by physician Margaret Todd in 1909.

Origin: Greek · First attested 1913

Class of 1913 isotope joined the language around 1913.

autistic crossword Pollyanna

See the full Class of 1913 →

Rhymes for isotope

ope pope mope rope dope hope lope nope cope trope slope grope

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Frequently asked questions

What does “isotope” mean?

The word “isotope” means one of two or more versions of a chemical element that have the same number of protons but a different number of neutrons. In plain terms, a variant of a chemical element that has extra or fewer neutrons in its atoms, but the same number of protons.

How do you pronounce “isotope”?

“Isotope” is pronounced EYE-suh-tohp (/ˈaɪ.sə.toʊp/ in IPA).

How do you use “isotope” in a sentence?

Here is “isotope” used in a sentence: “Carbon-14 is a radioactive isotope used to date ancient bones.”

What part of speech is “isotope”?

“Isotope” is a noun.

Where does the word “isotope” come from?

The word “isotope” dates back to around 1913 and comes from Greek. From Greek iso- ("same") plus -tope ("place"), because isotopes occupy the same position in the periodic table. Coined in 1913 by chemist Frederick Soddy, building on a suggestion by physician Margaret Todd in 1909.

Is “isotope” a common word?

“Isotope” is an uncommon word in modern English.