The Full Form of OVM is Open Verification Methodology.

The Open Verification Methodology (OVM) provides the first open, interoperable SystemVerilog verification methodology in the industry. The OVM provides a library of base classes that allow users to create modular, reusable verification environments in which components talk to each other via standard transaction-level modeling (TLM) interfaces. It also enables intra- and inter-company reuse through a common methodology and classes for virtual sequences and block-to-system reuse. As a joint development initiative between Mentor Graphics® and Cadence® Design Systems, the OVM is supported on multiple verification platforms making it the de facto standard methodology that is ideally suited to both novice and expert verification engineers.