device, appliance
The article is part of the word: el aparato. That way you learn the gender with it.
On the card “device”, ripiti also accepts la máquina. Not the other way round: for la máquina, el aparato is not accepted.
Remember el aparato for good. ripiti brings the word back just before you forget it, with these sentences. Free, no account needed, works offline.
practise el aparato in ripiti