Capsule vs Shell

When to use each in English, with meaning, register, and examples.

Capsule

Top 5,000 (fairly common)C1noun

Shell

Top 1,000 (very common)B1noun
Most common: Shell
 CapsuleShell
Pronunciation🇬🇧 //ˈkæpsjuːl//🇺🇸 //ˈkæpsəl//🇬🇧 /["/ʃel/"]/🇺🇸 /["/ʃel/"]/
MeaningA small container for medicine or other items.A hard outer covering of some animals, especially sea creatures.
ExampleShe took a capsule with water to relieve her headache.The turtle hid inside its shell to protect itself from predators.
RegisterNeutralNeutral
How commonTop 5,000 (fairly common)Top 1,000 (very common)
CEFR levelC1B1
Part of speechnounnoun
Collocationstime capsule, medication capsule, space capsule, gelatin capsule, dry capsuleempty, hard, outer, have, come out of, emerge from, unexploded, spent, anti-aircraft, load, fire, fly, fall, land, fire, shock, case, concrete, burned-out, empty
Antonymsexpansion, unfolding, openingcore, interior, inside
Common mistakesConfusing with 'capstone', which refers to a finishing stone., Using 'capsule' to refer to large containers., Mispronouncing with emphasis on the second syllable instead of the first.Confused with 'shelled' when referring to something that has been removed from the shell., Used inappropriately in contexts where 'case' or 'cover' would be more specific., Mispronounced as 'shelle' instead of 'shell'.
Usage notesUsed in medical contexts for pills and in general contexts for small containers. Avoid using in very casual settings.Used to refer to physical shells of animals like snails and turtles or as a protective cover for eggs. Not usually used in formal writing about technology unless specifying a computer shell.

Frequently asked questions: Capsule vs Shell

What's the difference between Capsule and Shell?

Capsule: A small container for medicine or other items. Shell: A hard outer covering of some animals, especially sea creatures.

Which is more common: Capsule and Shell?

Shell is the most common in everyday English.

Which is more advanced: Capsule and Shell?

Capsule is the highest level, at C1, on the CEFR scale.

Are Capsule and Shell the same CEFR level?

Capsule: C1, Shell: B1 on the CEFR scale.

What part of speech are Capsule and Shell?

Capsule: noun, Shell: noun.

Can you show an example of each?

Capsule: She took a capsule with water to relieve her headache. Shell: The turtle hid inside its shell to protect itself from predators.

Can I use Capsule and Shell interchangeably?

Not always. Capsule and Shell are related and overlap in some contexts, but they differ in register, how common they are, and usage, so swapping one for another can change the meaning or tone. Check the differences above before substituting.

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