mullion: meaning, definition, pronunciation and examples
C2Technical / Formal / Architectural
Quick answer
What does “mullion” mean?
A vertical bar or divider between the panes of glass (or lights) in a window.
Audio
Pronunciation
Definition
Meaning and Definition
A vertical bar or divider between the panes of glass (or lights) in a window.
A structural or decorative element dividing a window, door, or screen into panes. Can also refer to similar vertical elements in furniture or interior design, or, more broadly, any upright division.
Dialectal Variation
British vs American Usage
Differences
The term is identical in meaning and use. Regional spelling variations (e.g., 'centre' vs. 'center') in surrounding text do not affect the word itself.
Connotations
None beyond the architectural context.
Frequency
Equally infrequent in both dialects, used only in technical/architectural contexts.
Grammar
How to Use “mullion” in a Sentence
The [material] mullion divides the window.The window features [number] mullions.The glass is set within the mullions.Vocabulary
Collocations
Examples
Examples of “mullion” in a Sentence
verb
British English
- The windows were mullioned in the Tudor style.
American English
- The architect specified that the facade be mullioned with bronze.
adjective
British English
- The mullion design is characteristic of the period.
American English
- We offer mullion options in aluminum or fiberglass.
Usage
Meaning in Context
Business
Used in the context of construction contracts, window sales, or property descriptions.
Academic
Used in architectural history, design theory, or material science papers.
Everyday
Virtually never used. A non-specialist might say 'window divider' or 'that bar in the window'.
Technical
The primary register. Precisely defined in architectural drawings, glazing specifications, and restoration guides.
Watch out
Common Mistakes When Using “mullion”
- Misspelling as 'million'.
- Using it to refer to horizontal dividers (those are 'transoms').
- Pronouncing it as /ˈmjuː.li.ən/ (like 'million').
FAQ
Frequently Asked Questions
A mullion is a vertical divider between window panes. A transom is a horizontal divider. Together they create a grid.
No, it is a specialised architectural term. Most people would not use or need it in daily conversation.
Yes, though it's rare. 'To mullion' means to furnish or divide with mullions (e.g., 'a mullioned window').
No. Modern picture windows or large glass curtain walls often have no mullions. They are typical in traditional multi-pane windows.
A vertical bar or divider between the panes of glass (or lights) in a window.
Mullion is usually technical / formal / architectural in register.
Mullion: in British English it is pronounced /ˈmʌl.i.ən/, and in American English it is pronounced /ˈmʌl.jən/. Tap the audio buttons above to hear it.
Phrases
Idioms & Phrases
- “None”
Learning
Memory Aids
Mnemonic
Imagine a MILLION windows, each with a vertical bar in the middle. The bar that makes the division is the MULLION.
Conceptual Metaphor
ARCHITECTURAL ELEMENTS ARE BODY PARTS (e.g., the mullion is the 'spine' or 'rib' of the window).
Practice
Quiz
What is a 'mullion' primarily?