Definition
Propaganda is communication produced and distributed with the specific intent of changing the audience's beliefs, emotions, or behaviour in favour of the producer's political or military objectives. It can be entirely true, entirely false, or a selective truth — what makes it propaganda is the purpose, not the accuracy.
Not just lies
The most effective propaganda is usually accurate on its content and misleading on its framing. Highlighting one civilian casualty event is propaganda even if the event happened — the propaganda is in the editorial choice of which events to foreground, not in the factuality of the event.
Both sides, always
Every government and most political movements engage in propaganda. The relative scale and sophistication differ, but the practice is universal. Reader literacy is the only durable defence — algorithmic content moderation alone has not solved it and will not.