watch-glass
LowFormal / Technical
Definition
Meaning
A small, shallow, circular glass dish, often slightly concave, used in laboratories.
1. The protective glass crystal covering the face of a watch. 2. The glass disc used in a pocket watch or the protective covering on a wristwatch dial. 3. Something resembling the shape of a watch crystal, such as the domed top of a chemical clock jar.
Linguistics
Semantic Notes
In lab contexts, it is a specific piece of equipment for holding samples during evaporation or weighing. In horology, it is a protective component. The primary modern technical use is scientific. The horological sense is more historical/niche but understood in relevant fields.
Dialectal Variation
British vs American Usage
Differences
No significant difference in meaning. Both use the term in scientific contexts. In horology, 'crystal' (US) or 'glass' (UK) is more common for the watch component, making 'watch-glass' less frequent in everyday talk about watches.
Connotations
Neutral technical term in both varieties. In the UK, the horological term 'glass' might be slightly more recognizable than in the US, where 'crystal' is dominant.
Frequency
Very low frequency in general language. Higher frequency in technical/scientific writing, equally low in both varieties.
Vocabulary
Collocations
Grammar
Valency Patterns
place X on a watch-glassuse a watch-glass for Ycover the beaker with a watch-glassVocabulary
Synonyms
Strong
Neutral
Weak
Vocabulary
Antonyms
Phrases
Idioms & Phrases
- “Under the watch-glass (metaphorically: under close observation or in a protected environment).”
Usage
Context Usage
Business
Rare. Might appear in procurement for laboratory supplies or watch repair services.
Academic
Common in chemistry, biology, and materials science lab manuals and papers.
Everyday
Very rare. Possibly used by hobbyists in watch repair or chemistry.
Technical
Standard term in laboratory procedures and horology (though 'crystal' is more modern for watches).
Examples
By Part of Speech
adjective
British English
- The watch-glass dish was carefully sterilised.
- A watch-glass replacement service is offered.
American English
- The watch-glass dish was carefully sterilized.
- A watch-glass replacement service is offered.
Examples
By CEFR Level
- The chemist placed the powder on a watch-glass to weigh it.
- The old pocket watch had a cracked watch-glass.
- To observe crystal formation, leave the solution to evaporate on a watch-glass.
- He carefully prized the damaged watch-glass from the vintage timepiece.
- The precipitate was collected on a tared watch-glass and desiccated to constant weight.
- In horological restoration, sourcing a period-correct convex watch-glass can be challenging.
Learning
Memory Aids
Mnemonic
Imagine a tiny, glass pond (the watch-glass) on the face of a watch, or a mini glass pond in a lab where samples swim before evaporating.
Conceptual Metaphor
PROTECTION IS A COVERING (horology); A CONTAINER IS A PLATFORM (laboratory).
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Do not translate as 'часы-стекло' (nonsensical). The lab item is 'часовое стекло' or 'стекло для часов' in specific contexts, but better to use 'кристалл часов' for the watch part and 'часовое стекло' as a lab dish loan translation.
- The compound is a single concept, not 'watch' + 'glass' independently.
Common Mistakes
- Using 'watch glass' (without hyphen) in formal technical writing where hyphenation is standard. Confusing it with a 'magnifying glass' for watch repair. Using it to refer to a drinking glass in the shape of a watch (non-standard).
Practice
Quiz
In which field is 'watch-glass' a standard piece of equipment?
FAQ
Frequently Asked Questions
It is a hyphenated compound noun: 'watch-glass'.
It's technically correct but old-fashioned. Modern watch enthusiasts and repairers almost always say 'crystal' for the protective cover.
It is used for holding small amounts of solid chemicals during weighing, evaporation, or for use as a cover for beakers to prevent splatter while allowing gas exchange.
They are similar and often used interchangeably. A watch-glass is typically more shallow and curved like a lens, while an evaporating dish might have a spout and be deeper, but the functions overlap.