Do you consider these three entities mentioned in title same thing or different? If latter, what's difference between each of these entities?
Mate, long term traders is just a literally word to describing a Trader(s)that has been into trading for many years, An investor is one that has invested in crypto, stocks, commodity, or other businesses either on the long or short term basis. A Holder could also be simply called an investor, though he/she may just be holding certain coins for a short time to maximize profit at any slight opportunity as the market make little move up.
As I have explained, these three entities has some differences but some times many people can term a Holder to be thsame as an Investor especially on the crypto community. As a matter of facts, they all have different meaning when you check the Advance English Dictionary.