Understanding transaction input and ouput

The definition you found is wrong. There is no such thing as a “from” address, nor a “Bitcoin account”.

Think about the Bitcoin system as coins. As for physical coins, you spend them entirely and may get new coins back in change. Contrary to physical coins, these coins are public so anyone can “grab” them therefore there must be a way for only the “owner” of the coin to be able to successfully use them. This is essentially what an address is.

The coins are transaction outputs. “Grabbing” a coin is referencing a transaction output in a new transaction’s input. Proving the ownership is done by providing data in this input to fulfill the challenge set by the address in the output you reference.

Therefore, to get back specifically to your question(s), in your screenshot the application displays the output referenced by this transaction input as it’s where interesting information is present (value of the coin and how to unlock it). And you can certainly lock multiple coin to the same address. In fact this transaction unlocks 3 coins that where locked in the same way (therefore “at the same address”).