Reader Jennifer W. recently contacted me with this question:

Could you look into the proper spelling of the term inkjet? I see it spelled 3 ways: ink jet, ink-jet and inkjet. There are differences between various dictionaries as well. How do I know which is correct?

Here was my response:

Jennifer,

Thanks for contacting me. It’s an excellent question!

If you are referring to an individual jet built into a printer, then “ink jet” would be correct. For example: “An ink jet in the printer became clogged with ink residue.”

But you should never use “ink jet” to modify a noun (such as “printer”). When you use two nouns together to modify a third noun, you must hyphenate the first two nouns. Otherwise, for example, you leave the reader wondering whether “ink jet printer” refers to a printer that uses one or more ink jets OR to a “jet printer” (whatever that is!) that uses ink (versus, say, toner(s) or color stick(s)).

This leads to the question about when to use ink-jet and when to use inkjet.

You may not like the answer, but in my opinion the answer is that you may use either one.

It depends on whether you prefer hyphenated or non-hyphenated compound nouns.

The German language is full of non-hyphenated compound nouns.

In contrast, British English is full of hyphenated compound nouns.

My impression is that many Americans prefer the German approach, and this approach is fine when combining ink and jet.

Omitting the hyphen does not always work, though. For example, “pen-island” can easily be misinterpreted when you omit the hyphen!

But, again, the non-hyphenated “inkjet” form is just as clear as the hyphenated “ink-jet” form.

And it seems to me that many people now prefer “inkjet” over “ink-jet” when you are omitting the word “printer” from your sentence — as in, “My inkjet died last week.” (or “Do you have any inkjets for less than $100?”).

…

Best,
Kirk

One suggestion: Buy my How to Use Hyphens book. It will help you further with questions like this.