What is an onus transaction?

Excuse me, could you please clarify what exactly an onus transaction is? I've come across the term in a few articles about blockchain and cryptocurrency, but I'm still a bit confused about its specific meaning and how it differs from other types of transactions. Is it a unique feature of a particular blockchain or cryptocurrency, or is it a more general concept? Could you provide a concise yet comprehensive explanation of what an onus transaction entails, and perhaps give an example or two to help illustrate the concept? Thank you in advance for your assistance.