so
UK[səʊ]US[soʊ]
adv
To such a great extent
adv
To the same extent (often followed by 'as')
adv
In the way described or demonstrated; thus
conj
And for this reason; therefore
interj
Used to express surprise, comprehension, or to introduce a conclusion
Etymology
The word 'so' is a foundational and ancient adverb in English, tracing directly back to the Old English 'swā', meaning 'in this way, to such an extent'. Its origins lie in Proto-Germanic 'swa', which itself descends from the Proto-Indo-European reflexive particle 'swe', meaning 'self'. This deep root connects to concepts of identity and manner. The core semantic journey is from the literal sense of 'in that specific manner' to a wide range of intensifying, comparative, and consequential meanings. Its simplicity and versatility have made it one of the most frequently used and functionally diverse words in the language, evolving from a simple demonstrative of manner into a crucial connective for logic and emphasis.
Analysis
This is a simplex word of Old English origin. It functions as an adverb, conjunction, and interjection.
Examples
The box was so heavy I could barely lift it.
She is not so tall as her brother.
I was tired, so I went to bed early.