I've heard both terms, but I can't differentiate between the two.
I've never seen ops dev used before this post. Searching around I see things like this article that has it in the title but nowhere in the article. Then there's this article from 2015:
So in this way, when “OpsDev” happens, IT ops teams are helping developers do their jobs, but developers are also architecting applications with IT ops in mind, helping them utilize resources better. The days of developers simply creating applications and “throwing them over the fence” to testers and IT ops teams are over.
which seems to define OpsDev as "development in a company that practices DevOps" (or more cynically, "development done correctly").
Finally, there's https://dzone.com/articles/opsdev-is-coming :
What Is OpsDev? OpsDev means that the dependencies of the various application components must be understood and modeled first before the development process begins. In addition, the consideration for infrastructure stability, environment modeling, security and audit/compliance measures are first and foremost. Application components are stubs and they do not need to be in their final forms. Secondly, the environments in which the components will be deployed for production must be modeled. Thirdly, the processes to deploy the various components to the target environments must be automated as much as possible.
Again, this sounds to me just like normal, modern development.
DevOps is a problematic term because it has many different definitions. OpsDev, on the other hand, appears to have essentially no definitions. From a personal perspective, I would mentally substitute "development" for every instance of "OpsDev" and ignore the term; it appears to be just another instance of people inventing new terminology to describe old concepts so that they sound more exciting.
In the operations team DevOps does not trust developers to make changes to the production infrastructure. Developers want to focus on their application and the value it delivers to the organization. Developers want to know the characteristics of the infrastructure but do not want to build it or operate it.
The operations team is absolutely critical to the success of DevOps methodologies.
The developers must be able to trust that the infrastructure has specific characteristics: characteristics like performance, connectivity, availability, and uniformity.
To enable this trust, I believe that the operations teams are going to need to become more like developers. I call this OpsDev.
OpsDev is not simply about having a scripted build for servers. OpsDev is about having a full infrastructure that is built and maintained automatically from a set of source-controlled configuration files, and then having development and test environments that are built using the same methodology.