Cool MateFormerly vs Once vs Previously
When to use each in English, with meaning, register, and examples.
Formerly
Once
Previously
| Formerly | Once | Previously | |
|---|---|---|---|
| Pronunciation | 🇬🇧 /["/ˈfɔːməli/"]/🇺🇸 /["/ˈfɔːrmərli/"]/ | 🇬🇧 /["/wʌns/"]/🇺🇸 /["/wʌns/"]/ | 🇬🇧 /["/ˈpriːviəsli/"]/🇺🇸 /["/ˈpriːviəsli/"]/ |
| Meaning | in the past; before now | one time | Before now; earlier. |
| Example | Namibia, formerly known as South West Africa | Once I finished my homework, I went out to play. | The building had previously been used as a hotel. |
| Register | Formal | Neutral | Neutral |
| How common | Beyond 10,000 (less common) | Top 1,000 (very common) | Top 2,000 (common) |
| CEFR level | B2 | A1 | B1 |
| Part of speech | adverb | adverb | adverb |
| Collocations | formerly a leader, formerly known, formerly used | once a week, once in a lifetime, once again, once more | previously mentioned, previously discussed, previously stated, previously introduced, previously reported |
| Antonyms | currently, now | never | subsequently, afterwards |
| Common mistakes | Confused with 'formally' — 'formerly' relates to the past, while 'formally' relates to official contexts., Omitting it when describing past roles or states, which can lead to ambiguity. | Confused with 'once' for 'twice' or other frequencies., Using 'once' with present tense when referring to past events. | Using 'previous' instead of 'previously' in a sentence., Confusing 'previously' with 'currently' which means now., Misplacing 'previously' in a sentence and changing the meaning. |
| Usage notes | Use 'formerly' to describe something that was true in the past but is no longer the case. It is more formal than saying 'used to'. Avoid in casual conversations. | Use 'once' to refer to something happening a single time in the past. It's neutral and often used in storytelling. It wouldn't be appropriate in highly formal writing. | Use 'previously' to connect past events with the present. It's suitable for both spoken and written contexts but may sound too formal in casual conversations. |
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Frequently asked questions: Formerly vs Once vs Previously
What's the difference between Formerly, Once, and Previously?
Formerly: in the past; before now Once: one time Previously: Before now; earlier.
Which is more formal: Formerly, Once, and Previously?
Formerly is the most formal of these.
Which is more common: Formerly, Once, and Previously?
Once is the most common in everyday English.
Which is more advanced: Formerly, Once, and Previously?
Formerly is the highest level, at B2, on the CEFR scale.
Are Formerly, Once, and Previously the same CEFR level?
Formerly: B2, Once: A1, Previously: B1 on the CEFR scale.
What part of speech are Formerly, Once, and Previously?
Formerly: adverb, Once: adverb, Previously: adverb.
Can you show an example of each?
Formerly: Namibia, formerly known as South West Africa Once: Once I finished my homework, I went out to play. Previously: The building had previously been used as a hotel.
Can I use Formerly, Once, and Previously interchangeably?
Not always. Formerly, Once, and Previously are related and overlap in some contexts, but they differ in register, how common they are, and usage, so swapping one for another can change the meaning or tone. Check the differences above before substituting.