Bitcoin as a technology is too complicated to comprehend it by reading only 1 article If you want to fully understand what BTC is better get the book by Kalle Rosenbaum "Grokking Bitcoin", available on Amazon. It is quite thick (about 500 pages) but after reading it I am sure that you will have no questions unansweredTo quote from a fairly comprehensive article on Bitcoin that I think is a good definition:
"Bitcoin is an electronic store of value and medium for trade, that uses a combination of algorithms and other code to replace the need for a trusted central bank, and allows for quasi-anonymous direct transfers of value between peers, without middlemen."