A Quiz on Treatment of 75 Compound Words

By Mark Nichol

Open, hyphenated, or closed? Usage guides, dictionaries, and style manuals may differ in their treatment of the following words, so there’s not necessarily one right answer — except for the purposes of this exercise: Merriam-Webster’s Collegiate Dictionary. All terms in this list are treated as open compounds. Which ones should be left as is, and which should be hyphenated or closed, and in which usages? The correct forms according to Merriam-Webster are listed at the bottom of the page.

1. Air borne
2. Anti social
3. Audio visual
4. Back log
5. Blood pressure
6. Book keeping
7. Bull’s eye
8. By law
9. Catch all
10. Check book
11. Child like
12. Clearing house
13. Court martial
14. Crew neck
15. Cross reference
16. Dog sled
17. Father land
18. Far reaching
19. First hand
20. Free style
21. Freeze dried
22. Fresh water
23. Go between
24. Great uncle
25. Half brother
26. High school
27. Higher ups
28. House hold
29. Inter agency
30. Key word
31. Jewel like
32. Land mass
33. Life size
34. Light year
35. Long term
36. Lower case
37. Main frame
38. Mass produced
39. Mid week
40. Mother ship
41. Multi purpose
42. Near collision
43. North west
44. Off shore
45. On site
46. Over supply
47. Pine cone
48. Pipe line
49. Policy maker
50. Post war
51. Pre existing
52. President elect
53. Pro life
54. Pseudo intellectual
55. Quasi realistic
56. Real time
57. Record breaker
58. River bed
59. Sea coast
60. Self control
61. Semi final
62. Shell like
63. Six pack
64. Snow melt
65. Socio economics
66. Step mother
67. Stomach ache
68. Strong hold
69. Toll free
70. Two fold
71. Under water
72. Vice president
73. Wild life
74. World wide
75. Year round


1. Airborne
2. Antisocial
3. Audiovisual
4. Backlog
5. Blood pressure (in the dictionary, so never hyphenate, except when combined with another adjective, as in “high-blood-pressure medication”)
6. Bookkeeping
7. Bull’s-eye
8. Bylaw
9. Catchall
10. Checkbook
11. Childlike
12. Clearinghouse
13. Court-martial
14. Crew neck (in the dictionary, so never hyphenate)
15. Cross-reference
16. Dogsled
17. Fatherland
18. Far-reaching
19. Firsthand
20. Freestyle
21. Freeze-dried
22. Freshwater
23. Go-between
24. Great-uncle
25. Half brother (in the dictionary, so never hyphenate)
26. High school (in the dictionary, so never hyphenate)
27. Higher-ups
28. Household
29. Interagency
30. Keyword
31. Jewel-like (because of the collision of two ls)
32. Landmass
33. Life-size
34. Light-year
35. Long term (hyphenate only when the phrase modifies a following noun)
36. Lowercase
37. Mainframe
38. Mass-produced
39. Midweek
40. Mother ship (in the dictionary, so never hyphenate)
41. Multipurpose
42. Near collision (hyphenate only when the phrase modifies a following noun)
43. Northwest
44. Offshore
45. On-site
46. Oversupply
47. Pinecone
48. Pipeline
49. Policymaker (not in the dictionary, but other -maker constructions, such as winemaker, are closed; if it looks wrong, leave it open)
50. Postwar
51. Preexisting
52. President-elect
53. Pro-life
54. Pseudo-intellectual (not in the dictionary, bust pseudo- constructions in which the second word starts with a vowel, such as pseudo-event, are hyphenated; those in which the second word starts with a consonant, such as pseudopod, are closed)
55. Quasirealistic (not in the dictionary, but most quasi- constructions, such as quasiperiodic, are closed; it if it looks wrong, hyphenate it)
56. Real time (hyphenate only when the phrase modifies a following noun)
57. Record breaker (not in the dictionary, but all other compounds with breaker, such as “circuit breaker,” are open)
58. Riverbed
59. Seacoast
60. Self-control
61. Semifinal
62. Shell-like (hyphenate only because of the collision of the ls)
63. Six-pack
64. Snowmelt
65. Socioeconomics
66. Stepmother
67. Stomachache
68. Stronghold
69. Toll free (hyphenate when the phrase modifies a following noun)
70. Twofold (but hyphenate with a number, as in 10-fold)
71. Underwater
72. Vice president (always open, though other compounds containing vice, such as vice-regent and viceroy, are treated differently)
73. Wildlife
74. Worldwide
75. Year-round

Scoring guide

0-25 correct: Always look it up.
26-50 correct: Always look it up.
51-75 correct: Always look it up.

Click here to get access to 800+ interactive grammar exercises!


5 Responses to “A Quiz on Treatment of 75 Compound Words”

  • Leif G.S. Notae

    Very amusing scoring system, I got a chuckle out of it.

    Good list here and great way to get the brain working on a cold, rusty Friday. I think the one catching my eye is #40, I thought most people wrote the word closed instead of open (unless my unhealthy obsession about ship being mothers has finally pushed me over the edge), but I could be wrong.

    Great article, thanks for sharing with us!

  • Tony Hearn

    Mark is quite clear that he is dealing with US usage as recorded in Merriam-Webster.

    I thought, nonetheless, it might be of interest to compare British and U.S. approaches. So I have trawled the Shorter Oxford English Dictionary and the Collins English Dictionary. This reveals some interesting outcomes:

    1) British usage differs at all in only 23 of the 75 cases in the first spelling offered in one or other dictionary. In 66 cases the same spelling as M-W is allowed by one or other authority. Two words are fairly confined to North America.

    2) The SED is more conservative than the CED.

    3) British usage tends slightly to favour open or loose compounds.

  • Tony Hearn

    And to complete the previous post, here’s the list of variants. SED = Shorter Oxford Dictionary, CED = Collins English Dictionary:

    8. Bylaw (SED by-law, bye-law; CED bylaw, bye-law)
    9. Catchall (SED & CED catch-all – chiefly U.S. And Canadian (!))
    10. Checkbook (SED cheque-book, CED chequebook)
    11. Childlike (SED ditto; but also ‘child-like’. CED childlike)
    12. Clearinghouse (SED Clearing House (of the original institution; otherwise: clearing-house. CED clearing house)
    13. Court-martial (SED as a noun: ‘court martial’ (note the plural: ‘courts martial’, As a verb (coll.) ‘court-martial’ )
    14. Crew neck (in the dictionary, so never hyphenate) (CED gives ‘crew-neck’)
    16. Dogsled (CED ‘chiefly U,S and Canadian. British: dog sledge’)
    19. Firsthand (SED & CED ‘first-hand’ as adj.)
    25. Half brother (in the dictionary, so never hyphenate) (SED & CED half-brother)
    34. Light-year (SED & CED light year)
    36. Lowercase (SED lower-case. CED n. lower case; adj. lower-case)
    39. Midweek (SED mid-week; CED midweek)
    40. Mother ship (in the dictionary, so never hyphenate)
    47. Pinecone (SED pine-cone; CED pine cone)
    48. Pipeline (SED pipe-line; CED pipeline)
    51. Preexisting (SED Pre-existing)
    52. President-elect (CED President elect)
    55. Quasirealistic (not in the dictionary, but most quasi- constructions, such as quasiperiodic, are closed; it if it looks wrong, hyphenate it) (SED ‘treated as a prefix and hyphenated’. All CED forms are hyphenated)
    59. Seacoast (SED sea-coast; CED seacoast)
    64. Snowmelt (SED has all snow- compounds hyphenated; CED varies)
    67. Stomachache (SED Stomach-ache; CED stomachache)

  • thebluebird11

    oooh…grrr…some of those…hmph….
    I’m not going to address all of the ones that I dislike, but #57, record-breaker and circuit breaker, I want to put my 2 cents in. I’m not going to fight a dictionary or style guide…not here, and not if I worked in a profession that required me to adhere to those guides. However, it seems to me that there’s a difference between the connotation of “breaker” here. A circuit breaker is a physical thing. A record-breaker is not; it’s more of an abstract noun, a concept. Kind of like heart-breaker and all that. So for example, the electrician might say to someone, “Where is the breaker?” and be understood (to mean circuit breaker). But if you said to someone, “Oh, that’s a breaker,” they would have no idea what you mean (record-breaker? heart-breaker?). IMHO I think it needs a hyphen.
    And I too enjoyed the scoring system at the end!

  • Sally

    Again, well done, Tony

    In addition to your variations, Tony, I would write ‘anti-social’ (and pronounce it ‘ant-EE’ not ‘ant-EYE’), ‘audio-visual,’ ‘book-keeping,’ ‘multi-purpose,’ ‘pine cone’ (not even hypenated), ‘post-war,’ ‘sea coast’ (never hyphenated, let alone as a single word), semi-final’ and ‘socio-economic.’ ‘Snowmelt’ is not even a word in the Macquarie Dictionary – I suspect another midwest-US-based loan-translation from German.

Leave a comment: