In Europa Universalis II, "minting" is the unofficial term for the process of raising money in the treasury via directing monthly income to the "To Treasury" slider on the budget screen. (Saying something like "sending monthly income to the treasury" all the time would just be too long.) "To mint" is a regular verb, having all the normal tenses (minted, will mint, etc.).
If you direct any of your monthly income into the "To Treasury" slider (that is, you mint it), then at the end of each month, that income is turned into money in your treasury. At the same time, you get some inflation. You can see the projected effect of minting on the budget screen, by setting the "To Treasury" slider then mousing over it. The tooltip will show how much income is projected, and how much inflation. Note that the income estimate is rough; in particular it does not project looting effects.