They're probably worth distinguishing somehow for newcomers. They're both transaction logs.
Ethereum is a transaction log with a consensus mechanism. Anyone can append to it. It's a scroll: any group or society can use apps that check the scroll to come to conclusions about the state of their interactions.
Urbit is a transaction log that only the owner can append to. It's a journal: users can safely append to their journal with any app, and their apps can read the whole journal to display data from multiple apps in desirable ways.
Ethereum is a transaction log with a consensus mechanism. Anyone can append to it. It's a scroll: any group or society can use apps that check the scroll to come to conclusions about the state of their interactions.
Urbit is a transaction log that only the owner can append to. It's a journal: users can safely append to their journal with any app, and their apps can read the whole journal to display data from multiple apps in desirable ways.