What does eighteenthly mean?
Eighteenthly is a rare English adverb formed on the pattern of 'firstly' and 'secondly', used to introduce the eighteenth item in an enumerated list of points. It combines the ordinal 'eighteenth' with the adverbial suffix '-ly', making its meaning entirely transparent even to readers encountering it for the first time. In practice, however, the word is seldom needed: enumerations rarely run to eighteen items, and when they do, writers overwhelmingly prefer the bare ordinal ('eighteenth,...') or abandon the numbered format altogether. When it does appear, it tends to occur in formal, legalistic, or deliberately archaic prose, or in humorous writing that mimics bureaucratic thoroughness. Because the '-ly' enumeration series grows progressively unwieldy after the first few ordinals, 'eighteenthly' functions less as a working vocabulary item than as a curiosity of English word-formation — a testament to how far the language's productive patterns can theoretically stretch, even where actual usage declines to follow.
adverbIn the eighteenth place or position in a sequence; used to introduce the eighteenth point in an enumeration, following the pattern of 'firstly', 'secondly', and so on.
- Used to introduce the eighteenth point or item in an enumeration or list.
"Eighteenthly, the committee addressed the outstanding question of funding for the new wing."
"Eighteenthly, the report turned to the question of staff accommodation."
"The lecturer worked methodically through his objections — seventeenthly the cost, and eighteenthly the delay to construction."
English happily gives us 'firstly' through 'twelfthly' and beyond — but almost nobody has ever needed to say 'eighteenthly' out loud.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of eighteenthly
The word is formed transparently within English from the ordinal adjective 'eighteenth', which derives from 'eighteen', itself a compound of 'eight' (from Old English 'eahta', cognate with Latin 'octo' and Greek 'oktō', all tracing to the Proto-Indo-European root *oktō(u)) and the suffix '-teen'. The adverbial suffix '-ly', from Old English '-līce', has been attached to ordinals since Middle English to produce enumeration adverbs such as 'firstly'. 'Eighteenthly' follows this fully regular pattern and requires no borrowing; its obscurity reflects the impracticality of very long enumerations rather than any irregularity in its formation.
How eighteenthly is actually used
Extremely rare and largely confined to formal, legal, or mock-formal enumeration. The '-ly' series (firstly, secondly, thirdly) becomes increasingly awkward beyond the first few ordinals, and writers typically switch to plain ordinals ('eighteenth') or restructure the list long before reaching this form. The word is transparent and understandable but will strike most readers as unusual or deliberately pedantic.
Easily confused with eighteenthly
'Eighteenth' is the ordinal adjective or noun referring to position number eighteen, while 'eighteenthly' is the rare adverbial form used to introduce the eighteenth item in a spoken or written enumeration.