Evidence, Then Conclusion
ことから presents a fact as the grounds for a judgement or a name.
- 指紋が残っていたことから犯人が分かった。(From the fingerprints left behind, they identified the culprit.)
The second half is a deduction, never a plain event. That is what separates it from から.
| Pattern | Second half |
|---|---|
| から | anything — a result, a plan, a request |
| ことから | a conclusion, an identification or a name |
The Naming Use
Its most distinctive job is explaining how something got its name:
- 桜が多いことから桜町と呼ばれている。(It's called Sakuramachi because of all the cherry trees.)
You will meet this constantly in place names, product names and dictionary entries.
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Formal and written — reports, news, explanations. In speech, から or ので does the same job.
Not ことだから
彼のことだから is a separate pattern meaning "knowing him", based on someone's character. Different construction, different meaning.
