Product Manager is ownership and commitment. Its role spans across all organizations: from figuring out what products to make (Strategy), ensuring that those products get made (Execution), and reporting back on how users respond to products (User Understanding). Sometimes the role may also include marketing, forecasting, and profit and loss (P&L) responsibilities.
In other words, Product Manager is a sort of CEO of the product, so you are the first responsible for the success (or failure) of your product.
Here my vision of what Product Management is: