What is Transaction (TX)?

In a blockchain context, a transaction (TX) generally refers to the sending and receiving of different types of data between users on a blockchain network. Depending on their origin, transactions can be sent with varying speeds and levels of security and privacy. The most common type of transaction simply allows users to exchange network-specific coins/tokens between each other. For example, Bob sends Linda four ether (ETH) using the Ethereum network, which she promptly receives a few minutes later. In exchange, Linda then sends Bob an equivalent value in bitcoin (BTC) via the Bitcoin network.