everyday (adj.) / every day (adv.): Style Guide Spelling Decisions (AP, Chicago, MLA, APA)

How major style guides rule on "everyday (adj.) / every day (adv.)"

Adjective ('everyday low prices') is one word; adverbial ('I run every day') is two. The single most common style-guide distinction.

The disagreement on "everyday (adj.) / every day (adv.)" is an example of closed adjective vs open adverbial phrase, the category of style-guide differences that most often confuses copy editors and creates inconsistency across long documents. Below is a guide-by-guide breakdown, drawn directly from the published editions cited.

What the divergence actually means

Unlike many compound-modernization decisions where style guides eventually converge, "everyday (adj.) / every day (adv.)" continues to show genuine divergence between major guides. The AP Stylebook treats this as a settled call; Chicago Manual leaves more flexibility; and Merriam-Webster, as a descriptive dictionary, records both forms. Source: Chicago Manual of Style, 17th Edition

The APA Publication Manual aligns with AP and Chicago on "everyday (adj.) / every day (adv.)", though APA generally addresses spelling questions only when they intersect with statistical reporting or technical psychology vocabulary. Where the manual is silent, APA defers to Merriam-Webster as its standard reference. Source: APA Publication Manual, 7th Edition

Merriam-Webster lists "everyday (adj.), every day (adv.)", which serves as the lexicographic baseline for U.S. style decisions. Because Merriam-Webster's entries reflect aggregated published usage rather than editorial preference, when a guide says "follow Merriam-Webster", as APA does, that effectively delegates the call to whichever spelling has dominated the published corpus. Source: Merriam-Webster Dictionary

Garner's Modern English Usage classifies the "everyday (adj.) / every day (adv.)" / "everyday (adverb)" pair on its Language-Change Index, a five-stage scale measuring whether a once-disputed form has been accepted into Standard English. For closed adjective vs open adverbial phrase, Garner's typically rates the dominant form at Stage 4 ("ubiquitous but objected to by traditionalists") or Stage 5 ("fully accepted"). Source: Garner's Modern English Usage, 5th Edition

Practical guidance for editors

For working writers, the practical rule is straightforward: in journalism, follow AP; in academic writing in the humanities, follow MLA or Chicago; in social-science publishing, follow APA; in book publishing, follow Chicago. When no house style applies, Merriam-Webster's main entry is the safest default. The differences across these guides on "everyday (adj.) / every day (adv.)" reflect not disagreement about correctness but different audiences and editorial pressures.

Editorial context

Copy editors most often stumble over the everyday/every day distinction by defaulting to the single-word form in adverbial positions, as in the erroneous I brush my teeth everyday, conflating it with the adjective despite identical pronunciation in speech. This error thrives because "everyday" visually echoes prolific one-word adverbs like anyway, someday, and nowadays, fostering an intuitive but misguided compounding urge, even as major dictionaries such as Merriam-Webster (since its 1909 New International edition) and the Oxford English Dictionary (attesting everyday adj. from 1661) enforce the split. Corpus analyses, including the Corpus of Contemporary American English, reveal the adverbial "everyday" comprising under 1% of relevant tokens in edited prose, yet it infiltrates journalism and trade books via rushed proofreading. Bryan Garner's Garner's Modern English Usage (5th ed., 2022) ranks it among the "top 50" common blunders, attributing persistence to analogical overgeneralization from informal registers where the two merge seamlessly.

Cross-references

For the dictionary entry, frequency data, and pronunciation of everyday, see the main word page. For other style-guide spelling decisions in this category, browse all style-guide spelling rulings.