What does fourthly mean?
Fourthly is an adverbial ordinal used to mark the fourth item in a structured sequence of points, most often in formal writing, debate, lectures, and presentations. It belongs to the family of '-ly' ordinals — firstly, secondly, thirdly, and so on — which signal enumeration explicitly and lend an air of methodical order to an argument. A speaker might say: 'Firstly, costs; secondly, timing; thirdly, staffing; and fourthly, long-term maintenance.' Although grammatically unimpeachable and long established, fourthly carries a slightly formal, even old-fashioned flavor today; many writers prefer the bare form 'fourth', and some style guides recommend it. Its value lies in clarity and rhythm: within a consistent series, it keeps each step of an argument visibly numbered, helping readers follow complex reasoning without losing track of where they are.
adverbFourthly introduces the fourth item in an enumerated list of points, following firstly (or first), secondly, and thirdly.
- Introduces the fourth in a series of enumerated points or arguments, typically in formal speech or writing.
"The plan has four stages: firstly, research; secondly, drafting; thirdly, review; and fourthly, publication."
"Fourthly, we must consider the environmental impact of the proposal."
"Firstly, define the problem; secondly, gather data; thirdly, test solutions; fourthly, implement the best one."
Style guides have scolded 'fourthly' for centuries — yet enumerations that abandon it for plain 'fourth' often end up looking less orderly, not more.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of fourthly
Fourthly derives from 'fourth', the English ordinal of the number four, itself rooted in the Old English 'fēowertha', from 'fēower' (four), a word with cognates across the Germanic languages (Old Frisian, Old Saxon, Old Norse). The '-ly' suffix marks it as an adverb, a construction that flourished in Early Modern English as writers sought explicit markers of enumeration. The underlying number four connects ultimately to the Proto-Indo-European root reconstructed as *kwetwores, whose Latin descendant 'quattuor' gave rise to related forms such as 'quartus' (fourth), whence words like 'quarter', 'quart', and 'quartet'.
Related word forms
How fourthly is actually used
Formal and somewhat old-fashioned in register; many modern style guides prefer simply 'fourth'. The '-ly' series (firstly, secondly, thirdly, fourthly) survives chiefly in formal argumentation, speeches, and academic prose. When one point is introduced with 'firstly', consistency favors continuing the series rather than mixing in 'second' or 'third'.
Easily confused with fourthly
'Fourth' is the ordinal position itself (or a fraction, as in 'a fourth of the total'), while 'fourthly' is an adverb used to introduce the fourth point in a sequence.