Word Lab
instrument · equipment · device
Usage — not pronunciation
The rule
Equipment is uncountable — the whole collection of tools or gear needed for an activity (never 'an equipment' or 'equipments'). Instrument and device are both countable, single items: instrument usually implies precision or a specialized, professional purpose (scientific, medical, musical), while device usually implies a mechanical or electronic gadget built for one practical function.
Quick tip
"Equipment" never takes "a/an" and never gets a plural -s — say "a piece of equipment" for one item. If you're stuck choosing between instrument and device: instrument leans toward science, medicine, or music; device leans toward everyday mechanical or electronic gadgets.
Correct
✓ “The lab has excellent equipment.”
✓ “I need a new piece of equipment.”
✓ “A thermometer is a scientific instrument.”
✓ “She plays several musical instruments.”
✓ “This device tracks your heart rate.”
Common mistake
✗ “The lab has excellent equipments.”
✗ “I need an equipment for this job.”
✗ “She bought three new equipments for the kitchen.”
When to use each word
instrument
- · Scientific or measuring tools: 'a measuring instrument', 'lab instruments'
- · Medical or surgical tools: 'surgical instruments'
- · Musical: 'play a musical instrument' — piano, violin, guitar
- · Countable: 'an instrument', 'several instruments'
equipment
- · Uncountable — never 'an equipment' or 'equipments'
- · The whole set of gear for an activity: 'camping equipment', 'office equipment', 'safety equipment'
- · One item within it: 'a piece of equipment', not 'an equipment'
device
- · A single mechanical or electronic gadget: 'an electronic device', 'a charging device'
- · Built for one specific practical function: 'a device for opening cans'
- · Countable: 'a device', 'several devices'
Full breakdown
The three words overlap because they can all describe the same physical object depending on context — a thermometer, for example, could reasonably be called a scientific instrument, a medical device, or just a piece of equipment in a hospital. What separates them is register and grouping, not the object itself. "Equipment" is a mass/collective noun, like "furniture" or "luggage" — it names the whole category of gear needed for an activity (camping equipment, safety equipment, kitchen equipment), and a single item within that category is "a piece of equipment," never "an equipment." "Instrument" and "device" are both ordinary countable nouns for a single item, but they carry different connotations: instrument suggests precision, skill, or a specialized field — surgical instruments, measuring instruments, musical instruments — while device suggests a self-contained gadget or mechanism built to do one practical job, often modern, mechanical, or electronic — a smoke detector, a charging device, a device for opening jars.
How teachers explain this
Approved tips from the community, sorted by helpfulness
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