A Marker Can Be a Pen, a Grave or a Debt
A marker is something that marks. The word covers pens, boundary stones, biological indicators and IOUs.
A marker is anything that marks something. The range is unusually wide: a felt pen, a boundary stone, a grave marker, a genetic marker indicating a condition, and in American slang an IOU. Medicine's use is now the most consequential — a *biomarker* is a measurable indicator of a biological state, and much of modern diagnosis depends on them.
- A pen. *A permanent marker.*
- An indicator or sign. *A boundary marker.*
- A biological indicator. *A tumour marker.*
- An IOU (American slang). *Calling in a marker.*
Word forms
| Form | Word | Example |
|---|---|---|
| Noun | marker | A black marker. |
| Plural | markers | Route markers. |
| Verb | mark | Mark the spot. |
| Compound | biomarker | A useful biomarker. |
| Related | landmark | A famous landmark. |
How it is used in a sentence
- A biomarker indicates a biological state.Medicine.
- He called in a marker.American: a favour owed.
- Put down a marker.Signal an intention.
Kinds of marker
- Permanent marker — waterproof ink
- Boundary marker — a stone or post marking a limit
- Genetic marker — a DNA sequence used to track inheritance
- Tumour marker — a substance indicating possible cancer
- Marker pen — the British term for a felt-tip
From *mark*, Old English *mearc*, a boundary or sign — related to *march* meaning a border region.
What is a biomarker?
A measurable indicator of a biological state, such as a protein in blood signalling inflammation or disease.
Where does *calling in a marker* come from?
From gambling, where a marker was a written IOU. Calling it in means demanding repayment of a favour.