cesium: meaning, definition, pronunciation and examples
C2Technical / Scientific
Quick answer
What does “cesium” mean?
A highly reactive, soft, silvery-gold alkali metal (chemical element with atomic number 55, symbol Cs).
Audio
Pronunciation
Definition
Meaning and Definition
A highly reactive, soft, silvery-gold alkali metal (chemical element with atomic number 55, symbol Cs).
1) The element used in atomic clocks, photoelectric cells, and as a catalyst. 2) The isotope cesium-137, a radioactive byproduct of nuclear fission used in medical radiotherapy and industrial gauges.
Dialectal Variation
British vs American Usage
Differences
Spelling: British English uses 'caesium'; American English uses 'cesium'. Pronunciation of the initial consonant follows the spelling difference (/ˈsiːziəm/ vs /ˈsiːziəm/).
Connotations
Identical scientific connotations. The British spelling aligns with other element names like sodium, potassium.
Frequency
Equally frequent in respective scientific registers. Virtually nonexistent in everyday conversation in both variants.
Grammar
How to Use “cesium” in a Sentence
Cesium + verb (reacts, oxidizes)Cesium + is + adjective (reactive, alkaline)Noun + of + cesium (atom of cesium)Cesium + noun (cesium compound)Vocabulary
Collocations
Examples
Examples of “cesium” in a Sentence
verb
British English
- The sample was caesium-doped to alter its electrical properties.
American English
- The process involves cesiating the photocathode to increase sensitivity.
adjective
British English
- The caesium-based standard is fundamental to timekeeping.
American English
- They developed a new cesium-ion propulsion system.
Usage
Meaning in Context
Business
Rare, except in specific industries like nuclear energy, precision timing, or specialty chemicals.
Academic
Common in chemistry, physics, nuclear engineering, and geology journals and textbooks.
Everyday
Extremely rare. Might be encountered in news about nuclear accidents or scientific breakthroughs.
Technical
The primary register. Used with precision in research, industry (e.g., drilling fluids), and technology (atomic clocks, GPS).
Vocabulary
Synonyms of “cesium”
Neutral
Weak
Watch out
Common Mistakes When Using “cesium”
- Misspelling: 'ceasium', 'ceseum'.
- Mispronunciation: /ˈkeɪziəm/ (incorrect, from misreading 'ce' as in 'celery').
- Confusing 'cesium' (element) with 'caesarean' (medical procedure).
FAQ
Frequently Asked Questions
Elemental cesium is highly reactive and pyrophoric (catches fire in air). The radioactive isotope cesium-137 is a hazardous contaminant that can cause radiation sickness and increase cancer risk.
Its main uses are in atomic clocks (defining the second), in photoelectric cells due to its low work function, in drilling fluids for the oil industry, and in medicine (cancer treatment with Cs-137).
The element was named from the Latin 'caesius' (sky-blue), for its spectral lines. British English retained the classical 'ae' ligature. American English systematically simplified many such spellings to just 'e' in the 19th century.
It is not recommended. International scientific unions (IUPAC) and British journals standardise on 'caesium'. Using 'cesium' may be marked as an Americanism or a spelling error.
A highly reactive, soft, silvery-gold alkali metal (chemical element with atomic number 55, symbol Cs).
Cesium is usually technical / scientific in register.
Cesium: in British English it is pronounced /ˈsiːziəm/, and in American English it is pronounced /ˈsiːziəm/. Tap the audio buttons above to hear it.
Learning
Memory Aids
Mnemonic
Think 'SEE-see-um' – you 'see' the silvery metal react violently when you 'see' it touch water.
Conceptual Metaphor
PRECISION (due to its use in atomic clocks): 'The experiment's timing was as precise as a cesium clock.'
Practice
Quiz
What is the primary reason for the spelling difference between 'caesium' and 'cesium'?