I've seen the word "byproduct" written several different ways and I'm wondering which is the preferred format? Is this a variation between US and British English or just a matter of a "house style?"
Learn English – Which is the preferred spelling, “byproduct,” “by-product,” or “by product?”
orthography
Related Solutions
Learn English – Is ‘useable’ preferred in certain regions, or just an alternate spelling of ‘usable’
When you switch to the World English version of Oxford Dictionaries Online, their definition of usable has this little "spelling help:"
Usable can also be spelled useable, with an e in the middle: both are correct.
The US version simply lists useable as an acceptable variant of usable, and omits the side note.
Etymonline shows usable as being derived from the Old French usable. It further notes that the word was "not common before c.1840," so it would seem that useable is not an "archaic form" that fell into disfavor.
I would guess that useable came to be an acceptable variant because of standard usage. I would note, however, that some dictionaries do not list useable at all.
There is no grammatical superiority or inferiority to open compounds (auto fill), hyphenated compounds (auto-fill) or closed compounds (autofill).
There are forms that are particularly common with particularly common compounds, to the extent that they would be considered preferred spellings. But even then it's common to find two or all three in good use.
There are also some compounds of long standing where all three are still often found (egg beater, egg-beater and eggbeater being an example).
There seems to be a general trend over the last few decades toward fewer hyphenated forms, and more closed forms, but not a so strong as to make hyphenated forms "wrong".
In all, there's little to pick between them. If anything would be objectionable to anyone, it would be the fact that they're relative neologisms, which some people dislike, and such people would prefer to just use "automatically filled in". But that's an objection of subjective taste of some people, not a rule of grammar. I would though avoid a neologism in a formal context, unless the formal text was on a related technical topic.
The only real way to pick between open, hyphenated and closed compounds are:
See what other people seem to prefer in the given case. Pay particular attention to those of the same region as yourself and writing in the same register as you intend to.
If you really just like the look of one more than another, and it's not particularly rare, then by all means go for it: It's an acceptable variation of personal style.
There are though two exceptions:
If a closed compound begins to be thought of as a fully independent word, then you should favour it. That said, if that happens you probably won't think of it as a closed compound yourself, so you won't make that mistake.
If a closed compound matches the spelling of a different word, then you should avoid it, to avoid confusion.
Best Answer
The OED lists two categories of words which begin "by" or bi; -see below. By-product belongs to the second category and is spelled with a hyphen.
To the first category belong such words as because (originally bycause). But the second category contains, among other things, those words already formed in Old English with by, or later words where "by" 'already has an attributive sense' -by-road, by-product, by-station etc.