That's an awfully strange way of putting it, I would just call it "cross-platform library". Isomorphism usually has the constraints of full inversion—this seems to imply you can render it on the server and serve it from the browser, and that's not being fulfilled at all. It's not even clear how anything would, as browsers are not typically set up to serve. It's also misleading to people who use the term outside of node servers.

I strongly recommend using "fully shared state" or "client-server application" or something to not imply anything more than DRY logic in javascript across the state of the blog. Otherwise it devalues both your work (doesn't fulfill people's expectations of isomorphism) and the word (it no longer has any meaning).

EDIT: To put it another way, I would expect a server to NOT BE NECESSARY for the client to work, just like clients aren't necessary for the server to function correctly.