English Reference

Word

manifold

Phoneticsman·i·fold, stress on the first syllable

US/ˈmænəˌfoʊɫd/

UK/mˈænɪfˌəʊld/

Countable noun TechnicalMathematics

Definition

n. a mathematical shape or space that looks flat and simple up close, even if it is curved and complex overall.

n. a topological space that locally resembles Euclidean space; in machine learning, the lower-dimensional curved surface embedded within a high-dimensional data space.

Examples

“The surface of the Earth is a two-dimensional manifold embedded in three-dimensional space.”

“The manifold hypothesis suggests that real-world images live on a smooth, low-dimensional surface within pixel space.”

“Non-linear dimensionality reduction algorithms like UMAP preserve the local geodesic geometry of the underlying data manifold.”

Examples

simple

“The surface of the Earth is a two-dimensional manifold embedded in three-dimensional space.”

contextual

“The manifold hypothesis suggests that real-world images live on a smooth, low-dimensional surface within pixel space.”

complex

“Non-linear dimensionality reduction algorithms like UMAP preserve the local geodesic geometry of the underlying data manifold.”

Usage

Typically used as an attributive adjective before a noun, or predicatively after a linking verb like 'be'.

Real-World Examples

“The questions running through the play are manifold, complex and echo those asked by sci-fi writers for decades: can robots hurt humans?”
The Guardian 11 Sept 2026

Etymology

From Old English manigfeald ('various, numerous, many-layered'), from manig ('many') + feald ('-fold'). Mathematically defined by Bernhard Riemann in 1851 (German Mannigfaltigkeit).

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

Related words

Domain

Mathematics

This entry

Exam level
CambridgeCambridgeCambridge English QualificationsThe exam suite from Cambridge University Press & Assessment, from A1 Movers up to C2 Proficiency. The benchmark names double as CEFR labels.C1 AdvancedIELTSIELTSInternational English Language Testing SystemThe 0–9 band test co-owned by the British Council, IDP, and Cambridge. Used for university entry, work, and migration.7.0–8.0TOEFL iBTTOEFL iBTTest of English as a Foreign Language, Internet-Based TestETS's academic English test, the standard route for US university admissions. Scored 0–120, with a 1–6 scale since 2026.1–6 scale: 5.0–5.595–113TOEICTOEICTest of English for International CommunicationETS's workplace English test, big in Japan and Korea. Listening & Reading scores 10–990 and tops out at C1.945–990
Frequency
Frequent
Level
C1 · Advanced
Updated

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