re-entrant
C1Formal / Technical
Definition
Meaning
Something (especially an angle or a landform) that points inwards, or re-enters a space from which it came.
A software subroutine or function that can safely be interrupted and called again (re-entered) before its previous invocation is complete. Also refers to a person returning to a profession or activity after a period away.
Linguistics
Semantic Notes
Primarily a technical term in geography, geometry, and computing. Its use for a person returning to a field (e.g., 're-entrant mother') is dated and less common today.
Dialectal Variation
British vs American Usage
Differences
Spelling preference: UK often uses hyphen ('re-entrant'), US may use hyphen or closed form ('reentrant'), especially in computing. The UK pronunciation /ˌriːˈɛntrənt/ is more common for the angle/geography sense. In US technical writing, 'reentrant' is dominant.
Connotations
Similar technical connotations in both varieties. No significant difference in implied meaning.
Frequency
Higher relative frequency in UK English for geographical descriptions (e.g., 're-entrant valley'). In US English, highest frequency is in computing contexts.
Vocabulary
Collocations
Grammar
Valency Patterns
[be] + re-entrant[have] + a re-entrant + [noun][design] + [object] + to be re-entrantVocabulary
Synonyms
Strong
Neutral
Weak
Vocabulary
Antonyms
Phrases
Idioms & Phrases
- “[No common idioms for this technical term]”
Usage
Context Usage
Business
Rare. Possibly in HR, referring to someone rejoining the workforce: 'a program for re-entrant professionals'.
Academic
Common in geography/geology papers describing landforms, and in computer science papers on concurrent programming.
Everyday
Virtually never used in casual conversation.
Technical
Primary domain. In computing: 'The routine must be re-entrant to avoid race conditions.' In cartography: 'The bay forms a significant re-entrant in the coastline.'
Examples
By Part of Speech
verb
British English
- [Not commonly used as a verb]
American English
- [Not commonly used as a verb]
adverb
British English
- [Not used as an adverb]
American English
- [Not used as an adverb]
adjective
British English
- The fortress wall had a re-entrant angle designed to trap attackers.
- The map showed a deep re-entrant in the glacial valley.
American English
- The reentrant code is essential for the multithreaded application.
- They fortified the re-entrant corner of the battlements.
Examples
By CEFR Level
- [This word is too advanced for A2 level]
- [This word is too advanced for B1 level. A simpler alternative is 'an inward curve'.]
- The bay formed a noticeable re-entrant in the otherwise straight coastline.
- In programming, a re-entrant function can be called by multiple threads safely.
- The defensive position was strengthened by exploiting a natural re-entrant in the terrain.
- To ensure thread safety, all shared library routines were meticulously crafted to be re-entrant.
Learning
Memory Aids
Mnemonic
Think RE-ENTER-ANT: a little ant that goes back into the hill, creating an inward path. The code/valley re-enters the space.
Conceptual Metaphor
A JOURNEY BACK IN: The path/code execution makes a return journey into a territory it has already visited.
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Avoid translating as 'повторно входящий' for the angle/valley sense; use 'вогнутый' or 'обращённый внутрь'. For computing, 'реентерабельный' is the standard term. Do not confuse with 'reentry' (космический корабль).
Common Mistakes
- Spelling: 'reentrent' (incorrect doubling). Pronunciation: stressing the first syllable only (/ˈriːntrənt/). Using it as a general synonym for 'returning' in non-technical contexts.
Practice
Quiz
In which field is the term 're-entrant' LEAST likely to be used professionally?
FAQ
Frequently Asked Questions
Yes, they are spelling variants of the same word. The hyphenated form (re-entrant) is more traditional and common in British English, especially for geographical features. The closed form (reentrant) is prevalent in American English and in global computing terminology.
Historically, yes (e.g., 'a re-entrant student'), but this usage is now dated and rare. Modern equivalents are 'returning' or 'comeback' (e.g., 'a returning officer', 'a comeback player'). The term is overwhelmingly technical today.
The direct antonym is a 'salient' angle—one that points outward, like the corner of a square. In more general terms, 'convex' is also an opposite to the 'concave' quality of something re-entrant.
Re-entrant code can be safely interrupted and called again (by another task or thread) before the first call finishes. This is crucial for multi-tasking operating systems, interrupt handlers, and multi-threaded applications, as it prevents data corruption and race conditions when shared routines are accessed concurrently.