so

/səʊ/

//səʊ// conj

By · According to Wiktionary data (CC BY-SA) ·

"so" is a 2-letter English headword indexed on PlainSpell.

The verdict

“so” is in the everyday core of English, ranked #33 in English word frequency and used as a conjunction.

#33
frequency rank, English
2
letters
20
confusable pairs

According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - Reduced form of 'so that', used to express purpose; in order that.

Visual similarity to commonly confused words

How many letter changes separate each confused pair (Levenshtein distance, normalized).

so vs SS
0% similar
so vs SP
0% similar
so vs su
50% similar

Source: PlainSpell confusable corpus (Wiktionary, CC BY-SA).

Key facts for so
PropertyValue
Headwordso
LanguageEnglish
Part of speechConjunction
IPA/səʊ/
Letters2
Frequency rank#33
Misspellings tracked0
Confusable pairs20
SourceWiktionary (kaikki.org)

Where “so” sits in English frequency

Every-word frequency runs from the handful of words we use constantly (left) to the long tail used once in a blue moon (right). so lands here:

#1#100#1K#10K#100K
← used constantlyrarely used →

Scale is logarithmic (each tick is 10× rarer). Source: FrequencyWords open word-frequency list.

Spelling & Dictionary Insight

The English entry for so is 2 letters long, classified as a conjunction, and transcribed in the International Phonetic Alphabet as /səʊ/. Corpus data places it at rank #33 in overall English word frequency, putting it firmly in the everyday core of the language. Wiktionary records 5 distinct senses for this headword, so context determines which meaning a reader should apply.

Zero misspellings are on record for so in our index, a sign its spelling follows regular English conventions. It also participates in 20 confusable-pair relationships, "SS", "SP", "su", and more, a pairing that trips writers up because the two words share enough sound or shape to blur together.

Etymologically, the entry records: From Middle English so, swo, zuo, swa, swe, from Old English swā, swǣ, swē (“so, as, the same, such, that”), from Proto-West Germanic *swā, from Proto-Germanic *swa, *swē (“so”), from Proto-Indo-European *swē, *swō (reflexive pronomial stem). Cognate with S… The correct English form is so, spelled S-O.

Definition

  1. 1
    Reduced form of 'so that', used to express purpose; in order that.
  2. 2
    As a result; for that reason; therefore; because of this; due to this.
  3. 3
    Used to connect previous conversation or events to the following question.
  4. 4
    Used to introduce a rhetorical question.
  5. 5
    Provided that; on condition that; as long as.

Etymology

From Middle English so, swo, zuo, swa, swe, from Old English swā, swǣ, swē (“so, as, the same, such, that”), from Proto-West Germanic *swā, from Proto-Germanic *swa, *swē (“so”), from Proto-Indo-European *swē, *swō (reflexive pronomial stem). Cognate with Scots sae (“so”), Saterland Frisian so (“so”), West Frisian sa (“so”), Dutch zo (“so”), German Low German so (“so”), German so (“so”), Danish så (“so”), Norwegian Nynorsk so (“so”), Swedish så (“so, such that”), Faroese so (“so”), Icelandic svo (“so”), Old Latin suad (“so”), Albanian sa (“how much, so, as”), Ancient Greek ὡς (hōs, “as”), Urdu سو (sō, “hence”).

Synonyms

so thatthat

This word in other languages

para que(Español)afin que(Français)damit(Deutsch)então(Português)

Definitions, pronunciation, and etymology for this entry are drawn from Wiktionary via the kaikki.org structured extract (CC BY-SA); frequency ordering uses the FrequencyWords open word-frequency list (2018 English corpus, MIT). See the methodology for how each field is sourced and updated.

Frequently Asked Questions

How do you spell "so"?
"so" is spelled S-O. The IPA pronunciation is /səʊ/.
What does "so" mean?
As a conjunction, "so" means: Reduced form of 'so that', used to express purpose; in order that.
What words are commonly confused with "so"?
"so" is commonly confused with "SS", "SP", "su". These words look or sound similar but have different meanings. PlainSpell provides detailed comparisons for each pair.
How do you pronounce "so"?
The IPA (International Phonetic Alphabet) transcription for "so" is /səʊ/. Click the speaker icon on the pronunciation badge above to hear it spoken aloud where audio is available.
What is the origin of the word "so"?
From Middle English so, swo, zuo, swa, swe, from Old English swā, swǣ, swē (“so, as, the same, such, that”), from Proto-West Germanic *swā, from Proto-Germanic *swa, *swē (“so”), from Proto-Indo-European *swē, *swō (reflexive pronomial stem). Cogn... See the full etymology section above for more details.
Is PlainSpell free to use?
Yes, PlainSpell is a completely free word reference. You can look up definitions, pronunciations, confusable pairs, homophones, and spelling corrections across 5 languages without any sign-up or subscription.

Using “so”

The practical upshot for anyone who landed here from a spell-check.

  • The one correct English spelling is S-O - every other letter order is a misspelling in standard orthography.
  • Say it as /səʊ/ (IPA); tap the speaker on the pronunciation badge to hear it where audio exists.
  • Don't mix it up with “SS” - see the side-by-side comparison. so vs SS
  • Browse more English words and confusable pairs in the same reference. English words
Data Source

Wiktionary (via kaikki.org), licensed under CC BY-SA & GFDL. Word ordering uses an open word-frequency list; misspelling variants are generated by edit-distance from the correct headword.

Source: Wiktionary (via kaikki.org) Structured Wiktionary extract

Source: FrequencyWords open word-frequency list FrequencyWords open word-frequency list