What does fifteenthly mean?
Fifteenthly is a rare adverb meaning 'in the fifteenth place,' used to introduce the fifteenth item in a numbered series of points or arguments. It belongs to a small family of ordinal adverbs — first(ly), second(ly), third(ly), and so on — formed by adding the adverbial suffix -ly to an ordinal number. In practice, words like fifteenthly appear almost exclusively in very formal enumeration: legal documents, parliamentary debate, or deliberately exhaustive lists. Because genuine lists seldom run to fifteen items, the word is more likely to be encountered as a humorous flourish than in everyday use; writers typically prefer finally or last when a long enumeration draws to a close. Though grammatically unremarkable, fifteenthly carries an unmistakable air of pedantry, and modern usage tends to exploit that quality for comic or rhetorical effect rather than out of necessity. Its value lies less in utility than in what it reveals about how English builds precise sequencing tools from number words.
adverbIn the fifteenth place in a sequence; used to introduce the fifteenth item in a list or enumeration.
- Used to mark the fifteenth point in an enumeration or ordered list.
"Fifteenthly, the committee turned its attention to the question of funding."
"Fifteenthly, we must consider the impact on local businesses."
"The speaker pressed on — twelfthly, thirteenthly, fourteenthly, and at last fifteenthly — until the audience had long since lost count."
Fifteenthly is one of those rare words that exists purely for people who refuse to stop listing things before item fifteen.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of fifteenthly
Fifteenthly is formed transparently within English from the ordinal number 'fifteenth' plus the adverbial suffix '-ly.' The underlying numeral traces back to Old English fīftēne (fif + tīene, 'ten'), which derives from Proto-Germanic roots shared across Germanic languages; cognates include German fünfzehn and Dutch vijftien. Ordinal adverbs of this pattern became productive in early modern English as writers sought explicit markers for extended enumerations, though only the lower ordinals (firstly, secondly) remain common today.
Related word forms
How fifteenthly is actually used
Highly formal and rare; almost always used with a touch of irony or humor, since real enumerations rarely reach fifteen points. Ordinary writing would use 'finally' or 'last' instead. Found mainly in legal, parliamentary, or satirical prose.
Easily confused with fifteenthly
Fourteenthly introduces the fourteenth item in a list, whereas fifteenthly introduces the fifteenth.