How major style guides rule on "log out (verb) / logout (noun)"
Same pattern as 'log in / login': verb open, noun closed. Often confused in UI button copy.
The disagreement on "log out (verb) / logout (noun)" is an example of phrasal verbs (open) vs derived nouns (closed), 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.
| Style guide | Preferred form |
|---|---|
| AP Stylebook (2024–2025 Edition) | log out (v.), logout (n.) |
| Chicago Manual of Style | log out (v.), logout (n.) |
| MLA Handbook | log out (v.), logout (n.) |
| APA Publication Manual | log out (v.), logout (n.) |
| Merriam-Webster Dictionary | log out (v.), logout (n.) |
What the divergence actually means
Unlike many compound-modernization decisions where style guides eventually converge, "log out (verb) / logout (noun)" 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 "log out (verb) / logout (noun)", 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 "log out (v.), logout (n.)", 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 "log out (v.) / logout (n.)" / "logout (verb)" pair on its Language-Change Index, a five-stage scale measuring whether a once-disputed form has been accepted into Standard English. For phrasal verbs (open) vs derived nouns (closed), 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 "log out (verb) / logout (noun)" reflect not disagreement about correctness but different audiences and editorial pressures.
Editorial context
In computing, particularly user interface design and software documentation, the closed logout persists as a verb despite formal style guides' consensus on the open log out, rooted in 1970s Unix conventions where logout served as both command and noun. This endures in button labels like Click Logout to end your session, prioritizing visual brevity, scannability, and historical continuity over phrasal-verb distinctions favored in print. Tech outlets such as ACM publications and developer portals from Oracle and Apple retain it, even as copy editors enforce open forms for consistency; refactoring UIs risks breaking accessibility standards or A/B testing results. By the early 2010s, C++ and Java API docs solidified this split, with corpus analyses of GitHub repositories showing logout verbs outnumbering opens 3:1 in code comments, underscoring a register divide between interactive digital contexts and edited prose.
Cross-references
For the dictionary entry, frequency data, and pronunciation of log, see the main word page. For other style-guide spelling decisions in this category, browse all style-guide spelling rulings.