APA capitalizes “Over” internally because it has four letters. Chicago 18 lowercases it when it is a short preposition but capitalizes it when it functions as an adverb; MLA treatment likewise depends on whether it is functioning as a minor preposition or a principal word. This guide keeps style-specific rules separate and marks grammatical ambiguity where the same spelling can play different roles.
ReviewedEvidence5 sourcesSectionWriting & Style
Quick answer
APA capitalizes “Over” internally because it has four letters. Chicago 18 lowercases it when it is a short preposition but capitalizes it when it functions as an adverb; MLA treatment likewise depends on whether it is functioning as a minor preposition or a principal word.
Key details
APA 7Capitalize internally under the four-or-more-letter rule
Automation NoteBoundary rules override ordinary internal treatment. Tokens with multiple grammatical roles remain review-only unless context is established safely.
Chicago 18POS-sensitive: lowercase as a short preposition, capitalize as an adverb or other principal word
MLA 9Normally lowercase as a preposition; principal-word uses are capitalized
Pos Sensitivity“Over” can function as more than a preposition, so Chicago/MLA automatic treatment needs context.
TermOver
Word Classpreposition / adverb
Style-by-style guidance
APA 7
Capitalize internally under the four-or-more-letter rule.
Chicago 18
POS-sensitive: lowercase as a short preposition, capitalize as an adverb or other principal word.
MLA 9
Normally lowercase as a preposition; principal-word uses are capitalized.
Important caveats
Automation boundary
Context can help identify the word’s role, but an ambiguous token should not be forced into a single title-case result.
Further guidance
Quick rule
APA capitalizes “Over” internally because it has four letters. Chicago 18 lowercases it when it is a short preposition but capitalizes it when it functions as an adverb; MLA treatment likewise depends on whether it is functioning as a minor preposition or a principal word.
Sources and evidence
Sources are shown with the role they play in this guide. Historical or style-sensitive claims are kept within the evidence boundary described above.
Prepositions are one of the clearest places where title styles diverge. APA uses a four-letter major-word threshold, Chicago 18 capitalizes prepositions of five letters or more, and MLA editorial guidance generally lowercases internal prepositions regardless of length.
APA title case capitalizes the first word, the first word of a subtitle, major words, and words of four letters or more while keeping short minor words lowercase in ordinary mid-title positions.
Chicago 18 uses title case for titles of works and changed a long-standing rule: prepositions of five letters or more are now capitalized. Shorter prepositions generally remain lowercase internally, while first and last words are capitalized and “to” remains lowercase as an infinitive marker in ordinary mid-title use.
MLA 9 describes title style as capitalizing the first word, last word, and all principal words. MLA’s public Style Center also documents the traditional lowercase treatment of internal prepositions, but its detailed preposition article is edition-labeled for MLA 8, so this engine does not yet treat the full MLA 9 converter profile as complete.
APA capitalizes “About” internally because it has at least four letters. Chicago 18 also capitalizes it when used as a preposition because current Chicago capitalizes prepositions of five letters or more. MLA treatment still depends on grammatical function, so prepositional and principal-word uses should not be collapsed into one rule.
APA capitalizes “Across” internally because it has at least four letters. Chicago 18 also capitalizes it when used as a preposition because current Chicago capitalizes prepositions of five letters or more. MLA treatment still depends on grammatical function, so prepositional and principal-word uses should not be collapsed into one rule.
APA capitalizes “Around” internally because it has at least four letters. Chicago 18 also capitalizes it because prepositions of five letters or more are capitalized. MLA ordinarily lowercases internal prepositions, while any principal-word use needs grammatical classification before an automated decision.
APA capitalizes “Between” internally because it has at least four letters. Chicago 18 also capitalizes it when used as a preposition because current Chicago capitalizes prepositions of five letters or more. MLA treatment still depends on grammatical function, so prepositional and principal-word uses should not be collapsed into one rule.
