time reversal: meaning, definition, pronunciation and examples
Low (Specialized)Academic / Scientific / Speculative Fiction
Quick answer
What does “time reversal” mean?
A theoretical or hypothetical concept where the sequence of events is reversed, moving backward in time instead of forward.
Audio
Pronunciation
Definition
Meaning and Definition
A theoretical or hypothetical concept where the sequence of events is reversed, moving backward in time instead of forward; also a symmetry principle in physics.
In physics: a fundamental symmetry principle stating that the laws of physics are invariant if the direction of time is reversed. In fiction/thought experiments: the hypothetical process of traveling backwards through time or reversing the flow of events.
Dialectal Variation
British vs American Usage
Differences
No significant differences in meaning or usage. Spelling of related terms may follow regional conventions (e.g., 'behaviour' vs. 'behavior').
Connotations
Neutral and technical in both variants.
Frequency
Equally low frequency in both academic/scientific registers.
Grammar
How to Use “time reversal” in a Sentence
[Subject] demonstrates/violates time reversal.Time reversal [verb] is a fundamental symmetry.Under time reversal, [process] would [result].Vocabulary
Collocations
Examples
Examples of “time reversal” in a Sentence
adjective
British English
- time-reversal symmetry
- a time-reversal invariant process
American English
- time-reversal symmetry
- a time-reversal invariant process
Usage
Meaning in Context
Business
Virtually never used.
Academic
Core concept in theoretical physics, particularly in quantum mechanics, thermodynamics, and particle physics.
Everyday
Extremely rare; only in discussions of time travel in science fiction.
Technical
Precise term for the symmetry transformation t → –t in physical equations.
Vocabulary
Synonyms of “time reversal”
Neutral
Weak
Vocabulary
Antonyms of “time reversal”
Watch out
Common Mistakes When Using “time reversal”
- Using 'time reversal' to mean simply 'going back in time' in casual conversation.
- Confusing 'time reversal' with 'time reversal invariance' – the latter is the property.
FAQ
Frequently Asked Questions
Not exactly. 'Time reversal' in physics is a symmetry principle. In casual fiction talk, it might be used loosely, but 'time travel' is the broader narrative concept.
No. Macroscopic processes are irreversible due to entropy (the second law of thermodynamics). Time reversal symmetry is studied at the microscopic level in particle physics.
The 'T' stands for 'Time'. T-symmetry is the technical abbreviation for time reversal symmetry.
No. While most fundamental laws respect it, certain rare processes in particle physics (like kaon decay) show a slight violation of T-symmetry.
A theoretical or hypothetical concept where the sequence of events is reversed, moving backward in time instead of forward.
Time reversal is usually academic / scientific / speculative fiction in register.
Time reversal: in British English it is pronounced /ˈtaɪm rɪˌvɜː.səl/, and in American English it is pronounced /ˈtaɪm rɪˌvɝː.səl/. Tap the audio buttons above to hear it.
Learning
Memory Aids
Mnemonic
Think of 'T' in 'T-symmetry' standing for 'Time' reversal.
Conceptual Metaphor
TIME IS A PATH THAT CAN BE WALKED BACKWARDS (in the theoretical sense).
Practice
Quiz
In which field is the term 'time reversal' used with the most precise technical meaning?