Firstly vs. Secondly vs. Thirdly – Which is Correct?

The words firstly, secondly, and thirdly are all grammatically correct adverbs used for enumerating points in a sequence. While valid, modern style guides often recommend the simpler forms first, second, and third as adverbs for the same purpose, particularly in less formal contexts.

Firstly, Secondly, or Thirdly – Which to Use?

All three words — firstly, secondly, and thirdly — are valid adverbs in American English, used to introduce items in a list or sequence, particularly in formal writing or speeches. Their primary distinction lies in their perceived formality and the common preference for their shorter counterparts. While perfectly acceptable, the trend in contemporary English leans towards using first, second, and third as adverbs for enumeration.

The “root cause” of the discussion isn’t about correctness, but rather stylistic preference and common usage. The “-ly” suffix typically denotes an adverb of manner, but in these cases, they function as adverbs of sequence.

For a more focused discussion on the nuances of these specific terms, explore the detailed comparison of First vs. Firstly.

The Best Trick to Remember the Difference

The best trick for remembering how to use firstly, secondly, and thirdly is the “Consistency Rule.” If you choose to use firstly to introduce your initial point, you should consistently follow with secondly, thirdly, and so on, for subsequent points. Conversely, if you opt for the more common first, then continue with second, third, etc. Mixing them — for example, “First, … Secondly, …” — is generally considered poor style.

Word	Part of Speech	Meaning	Example
firstly	Adverb	Used to introduce the first point in a sequence or list.	Firstly, we must consider the budget constraints.
secondly	Adverb	Used to introduce the second point in a sequence or list.	Secondly, we need to assess the available resources.
thirdly	Adverb	Used to introduce the third point in a sequence or list.	Thirdly, we should consult with the stakeholders.

How to Use Firstly

Firstly is an adverb that means “in the first place” or “as the first point.” It is primarily used to introduce the initial item in an ordered list of reasons, arguments, or steps. Its usage often signals a formal tone, making it common in academic papers, legal documents, formal speeches, and structured presentations. While grammatically sound, many contemporary style guides and editors suggest using the simpler “first” as an adverb for enumeration, reserving “firstly” for contexts where the “-ly” adverbial form is particularly desired for rhythm or formality.

Example 1: Firstly, the proposal lacks a clear timeline for implementation.

Example 2: To achieve our goals, firstly, we must define our objectives clearly.

Example 3: The judge stated, “Firstly, the defendant failed to appear; secondly, no legal representation was present.”

Etymology of the word Firstly

The word firstly derives from the Old English word fyrst, meaning “foremost, original,” which itself is a superlative of fore. The suffix “-ly” was added to first to form an adverb, a common practice in English to create adverbs of manner or sequence. Its usage as an enumerative adverb dates back to at least the 16th century, though its popularity has fluctuated over time.

How to Use Secondly

Secondly is an adverb used to introduce the second item in an enumerated sequence. It functions as “in the second place” or “as the second point.” Like firstly, it carries a formal connotation and is typically employed in structured arguments, explanations, or lists where a clear progression of points is necessary. When firstly is used to begin a list, secondly is the appropriate and consistent follow-up. Using it independently of firstly is possible but less common when listing points.

Example 1: The board discussed two issues: secondly, the impact of the new regulations.

Example 2: My reasons are as follows: firstly, the cost is too high; secondly, the quality is insufficient.

Example 3: We need to address two primary concerns. Secondly, the lack of community engagement presents a significant challenge.

Etymology of the word Secondly

Secondly is formed by adding the adverbial suffix “-ly” to the ordinal number second. The word second itself comes from Old French seconde, which originated from Latin secundus, meaning “following, next.” The construction secondly has been in use since the 14th century, demonstrating a long history of English speakers using this form for enumerating points.

How to Use Thirdly

Thirdly is an adverb used to introduce the third item in an enumerated list or sequence. It means “in the third place” or “as the third point.” Consistent with firstly and secondly, its use maintains a formal tone and is suitable for detailed explanations, formal presentations, or any context requiring a clear, structured flow of information. It should logically follow firstly and secondly to maintain parallel structure and clarity in a multi-point discussion.

Example 1: The committee decided to reform; thirdly, they would review all existing policies.

Example 2: There are three main steps: firstly, plan; secondly, execute; and thirdly, evaluate.

Example 3: The speaker outlined his plan, stating, “Thirdly, we must ensure long-term sustainability.”

Etymology of the word Thirdly

The word thirdly is derived from the ordinal number third, combined with the adverbial suffix “-ly.” The word third comes from Old English þridda, which has Germanic roots. Like firstly and secondly, the “-ly” suffix transforms the ordinal into an adverb used for sequencing. Its use as an enumerative adverb can be traced back to Middle English, reinforcing its established place in the English language for formal enumeration.

Related Concepts

Understanding broader grammatical concepts helps clarify the appropriate use of enumerative adverbs like firstly, secondly, and thirdly.

• Adverbs of Sequence: These adverbs (e.g., firstly, then, next, finally) indicate the order in which events or ideas occur. They are crucial for creating logical flow and coherence in writing.
• Parallelism: This is the use of components in a sentence that are grammatically similar in their construction, sound, meaning, or meter. When using enumerative adverbs, maintaining parallelism (e.g., consistently using “-ly” adverbs or consistently using simple ordinals) is key for good style.
• Formal vs. Informal Language: The choice between “firstly, secondly, thirdly” and “first, second, third” often comes down to the desired tone. The “-ly” forms are generally perceived as more formal, while the simpler ordinals are suitable for most contexts.

Examples from Media and Literature

• “Firstly, the report must be submitted by Friday. Secondly, it needs to be approved by the department head. And thirdly, we require a budget breakdown.” — (From a corporate memo, often reflecting formal business communication)
• “The author argued that the novel succeeded for three reasons: firstly, its compelling plot; secondly, its well-developed characters; and thirdly, its profound thematic depth.” — (From a literary critique)
• “To address the crisis, the government announced a three-pronged approach. Firstly, immediate relief efforts would be deployed. Secondly, long-term infrastructure repair would commence. Thirdly, preventative measures would be implemented.” — (From a news report on a disaster response, June 2, 2026)
• “In his philosophical treatise, he posited: ‘Firstly, all existence is interdependent; secondly, knowledge is subjective; thirdly, truth is elusive.'” — (From a philosophical text)

Practice Exercises

Choose the correct word to complete the sentence.

1. To begin, __________, ensure all equipment is calibrated.
2. The speaker noted two key points: __________, the economic impact; __________, the social implications.
3. My objections are clear: __________, the cost; __________, the timeline; and __________, the lack of resources.
4. Before making a decision, consider __________, the risks involved.
5. The research outlined three findings: __________, increased efficiency; __________, reduced waste; and __________, improved morale.

Answer Key

1. firstly (or first)
2. firstly, secondly (or first, second)
3. firstly, secondly, thirdly (or first, second, third)
4. firstly (or first)
5. firstly, secondly, thirdly (or first, second, third)

Firstly Synonyms

Synonym	Definition
First	As the initial point; before anything else (as an adverb).
Initially	At the beginning; at first.
To begin with	As a starting point; in the first instance.
In the first place	Primarily; as the foremost consideration.

Secondly Synonyms

Synonym	Definition
Second	As the next point after the first (as an adverb).
Next	Immediately after; subsequently.
Furthermore	In addition to what has been said; moreover.
In the second place	As the second consideration or point.

Thirdly Synonyms

Synonym	Definition
Third	As the point following the second (as an adverb).
Lastly	At the end; as the final point.
Finally	After a long time, or at the end of a series of actions.
In the third place	As the third consideration or point.

Frequently Asked Questions

Question 1: Are “firstly, secondly, thirdly” interchangeable with “first, second, third”?
While both sets of words can be used as enumerative adverbs, they are not always interchangeable in terms of style. “First, second, third” are generally preferred in modern writing for their conciseness and less formal tone, suitable for most contexts. “Firstly, secondly, thirdly” are more formal and are often used in academic, legal, or highly structured professional documents.

Question 2: Is it ever incorrect to use “firstly, secondly, thirdly”?
No, it is not grammatically incorrect to use “firstly, secondly, thirdly.” They are valid adverbs. However, using them inconsistently (e.g., “First, … Secondly, …”) or in overly informal contexts might be considered stylistically awkward or unnecessarily formal by some readers or editors.

Question 3: When should I choose “first, second, third” over “firstly, secondly, thirdly”?
You should generally choose “first, second, third” as adverbs for enumeration in most contemporary writing, including articles, blog posts, emails, and general reports. They are more common, less formal, and contribute to a more direct and accessible style. Reserve “firstly, secondly, thirdly” for contexts where a distinctly formal tone is desired and where you are consistently enumerating multiple points.

Conclusion

The choice between firstly, secondly, thirdly and their simpler counterparts first, second, third is primarily a matter of style and tone, rather than grammatical correctness. All are valid enumerative adverbs. While the “-ly” forms lend a more formal air, contemporary English often favors the concise first, second, third for most contexts. The most important takeaway is to maintain consistency: if you start with firstly, continue with secondly and thirdly.

Pro Tip: For clear, professional communication in 2026, opt for first, second, third in most situations to avoid sounding overly formal or archaic. If your audience or publication demands a highly formal register, then firstly, secondly, thirdly are appropriate, provided you use them consistently throughout your enumeration.