object glass
RareTechnical, Formal, Obsolete (in general use)
Definition
Meaning
The lens in an optical instrument (e.g., a microscope or telescope) which is closest to the object being viewed and receives the light rays from it.
Primarily used as a technical term for the objective lens in an optical system; in very rare figurative use, it can mean the primary medium through which something is viewed or perceived.
Linguistics
Semantic Notes
This is a historical or highly technical term. In modern English, the term 'objective' or 'objective lens' is almost universally preferred. 'Object glass' may still be encountered in antique instrument descriptions or older technical literature.
Dialectal Variation
British vs American Usage
Differences
No significant difference. The term is equally obsolete/technical in both varieties. If used, the British might be slightly more likely to retain it in historical contexts.
Connotations
Connotes historical, antiquated, or very precise technical language. No regional connotation.
Frequency
Extremely low frequency in both regions. Almost entirely supplanted by 'objective'.
Vocabulary
Collocations
Grammar
Valency Patterns
the [ADJECTIVE] object glass of the [INSTRUMENT]focus by adjusting the object glassVocabulary
Synonyms
Strong
Neutral
Weak
Vocabulary
Antonyms
Phrases
Idioms & Phrases
- “To look through the wrong end of the object glass (rare, for misunderstanding a situation)”
Usage
Context Usage
Business
Virtually never used.
Academic
Used only in historical or highly technical papers on optics; modern physics/engineering uses 'objective'.
Everyday
Not used.
Technical
The primary domain. Found in antique instrument manuals, restoration guides, or niche historical optics texts.
Examples
By CEFR Level
- The old microscope had a very small object glass.
- He carefully cleaned the object glass.
- The quality of the image depends heavily on the object glass at the end of the tube.
- Early telescopes used a single convex lens as the object glass.
- The achromatic object glass, invented in the 18th century, greatly reduced colour distortion in refracting telescopes.
- In his restoration of the antique orrery, the conservator had to source a period-correct object glass.
Learning
Memory Aids
Mnemonic
Think of the OBJECT being viewed, and the GLASS (lens) right next to it: the Object Glass.
Conceptual Metaphor
A WINDOW TO REALITY: The object glass is the first and most direct 'window' through which the instrument sees the world.
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Avoid literal translation as 'объектное стекло'. The correct modern equivalent is 'объектив' or 'объективная линза'. The old term 'объективное стекло' is a direct but obsolete equivalent.
Common Mistakes
- Using 'object glass' in modern technical writing instead of 'objective'.
- Confusing it with 'eyepiece' or 'ocular'.
- Hyphenating incorrectly (not 'object-glass').
Practice
Quiz
What is the modern, more common term for 'object glass'?
FAQ
Frequently Asked Questions
No, it's an obsolete term. The modern equivalent is 'objective' or 'objective lens'.
No, it specifically refers to the primary lens in an optical instrument that faces the object, such as in a telescope or microscope.
The eyepiece or ocular lens, which is the lens closest to the viewer's eye.
It's a descriptive compound: 'object' refers to the thing being viewed, and 'glass' refers to the lens (traditionally made of glass) that faces it.