Some people people believe they are one and the same, others believe it is only a matter of holding time. I disagree with both.
I believe an investor chases yields and value creation by providing capital & resources.
I believe a trader chases changes in yields and value fluctuation by managing assets & opportunity.
By those defintions, investors do not short, and are free to speculate, but they do not allocate capital to non-yield bearing assets (oil, gold, options, futures, indexes). Traders can have longer holding times than investors, and may have a broader view of macro-economic trends.
Heir go, I am both.