Word.ws English Dictionary

-in

-in suffix: a neutral chemical compound. Also the alternative form of -ing.

Suffix (1)

-in (noun-forming suffix, countable and uncountable, plural -ins)

  1. A neutral chemical compound.
    • albumin, casein, chitin, pepsin, saponin
  2. An enzyme.
    • renin, pancreatin
  3. An antibiotic.
    • penicillin, streptomycin
  4. A pharmaceutical product.
    • cobalamin, niacin, vitamin

Suffix (2)

-in (noun-forming suffix, plural -ins)

  1. Attached to a word (usually a verb) to denote a protest, demonstration or other type of gathering characterized by the activity denoted by the base word.
    • At Stanford 380 students volunteered to give blood for military and civilian casualties in South Viet Nam: Ohio State held a similar “bleed-in.”1965 November 19, “Universities: The Spectrum on Viet Nam”, in Time, volume 86, number 21, page 67

Also used as

-in is also the alternative form of -ing.

-in is also the alternative form of -en.

Forms of -in

plural-ins
alternative form-in’

Origin of -in

Clipping of -ine.

From the particle in, modelled after sit-in. Compare -off.

Emically usually held to be a clipping of -ing. Etically a prosodically coexistent alternative form thereof in some varieties.

Questions about -in

What does -in mean?
-in means a neutral chemical compound.
What part of speech is -in?
-in is a suffix.

Words near -in in the dictionary

  1. -imal
  2. -ime
  3. -imibe
  4. -imundo
  5. -imus
  6. -in
  7. -in'
  8. -in-law
  9. -in-waiting
  10. -ina
  11. -inator

Source and license

Adapted from Wiktionary: -in (page history and authors). Text available under the Creative Commons Attribution-ShareAlike 4.0 license. Word.ws reformatted the entry and added links. Wiktionary data of 2026-09-02.

Last updated:

Cite this entry: “-in.” Word.ws, https://word.ws/-in. Based on Wiktionary, CC BY-SA 4.0.