run in
MediumInformal/Technical
Definition
Meaning
To bring or break in something new (e.g., a car engine, machinery) by using it gently and carefully for an initial period.
To have a preliminary argument, disagreement, or brief conflict with someone. To include or insert something within a text or document. To bring something or someone into a particular place or situation. In cricket, the bowler's approach to the wicket before delivering the ball.
Linguistics
Semantic Notes
Primarily a phrasal verb. The meaning is often non-literal, especially in the 'argument' sense. In the 'engine' sense, it is a technical/mechanical term that has entered general usage.
Dialectal Variation
British vs American Usage
Differences
Slight preference for the 'engine break-in' sense in both, but the 'preliminary disagreement' sense is equally common in both varieties. The cricket-specific meaning is exclusively British/Commonwealth.
Connotations
In both varieties, 'run in' suggests a temporary or introductory phase (for machinery) or a minor, non-serious conflict (for people).
Frequency
The phrasal verb is moderately frequent. The noun form 'run-in' (e.g., 'I had a run-in with my neighbour') is more common than the verb form in everyday speech.
Vocabulary
Collocations
Grammar
Valency Patterns
[subject] run in [object] (e.g., He ran in the new engine.)[subject] have/run into a run-in with [object] (e.g., She had a run-in with her boss.)Vocabulary
Synonyms
Strong
Neutral
Weak
Vocabulary
Antonyms
Phrases
Idioms & Phrases
- “Have a run-in with someone/something”
- “Run it in gently”
Usage
Context Usage
Business
Rare. Possibly in 'We had a run-in with the regulators over the new policy.'
Academic
Very rare, except in historical narratives describing conflicts.
Everyday
Common: 'I need to run in my new car for the first 500 miles.' 'My son had a run-in with his teacher.'
Technical
Common in automotive/engineering contexts for the initial operation of machinery under specific conditions.
Examples
By Part of Speech
verb
British English
- Make sure you run in the new engine properly for the first thousand miles.
- The fast bowler had a long run-in before delivering the ball.
American English
- You should run in your new car according to the manual.
- I don't want to run in with the law.
adjective
British English
- The run-in period is crucial for engine longevity. (less common as adjective)
American English
- The run-in procedure is outlined in chapter three. (less common as adjective)
Examples
By CEFR Level
- I have a new car. I must run it in slowly.
- My neighbour and I had a little run-in about the parking space.
- Following the manufacturer's guidelines to run in the engine can significantly improve its performance over time.
- The journalist's run-in with the authorities was a precursor to the broader crackdown on the press.
Learning
Memory Aids
Mnemonic
Think of a new car RUNning INto your life; you have to treat it carefully at first (break it in), or you might RUN INto trouble with it.
Conceptual Metaphor
TREATING SOMETHING NEW CAREFULLY IS GENTLY RUNNING IT IN. A CONFLICT IS A PHYSICAL COLLISION (RUNNING INTO).
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Do not confuse with 'вбегать' (to run inside). 'Run in' is almost never used literally for physical movement into a space. The noun 'run-in' (разборка, стычка) is more common than the verb.
Common Mistakes
- *I ran in the house to get my keys. (Use 'ran into').
- *He runs in his new shoes. (Use 'breaks in' or 'wears in').
- Confusing 'run in' with 'run into' (meet by accident).
Practice
Quiz
What does 'run in' typically NOT mean?
FAQ
Frequently Asked Questions
No, it is mostly informal or technical. In formal writing, prefer 'break in' (for engines) or 'confrontation' (for arguments).
'Run in' means to break in or have a conflict. 'Run into' means to collide with something or meet someone by chance.
Yes, the hyphenated form 'run-in' is a common noun meaning a disagreement or conflict (e.g., 'a run-in with the boss').
This varies by manufacturer, but a typical run-in period is the first 600-1000 miles, involving varied speeds and avoiding high RPMs or constant speed.