Parboiling or leaching is a cooking technique where ingredients such as rice or potatoes are cooked in boiling water, but only so far as they are partly cooked.
Often, the final cooking of the ingredient is done using another cooking method such as roasting, grilling and frying.
For example potatoes are parboiled to soften them, which allows the outside of the potato to be roughed before roasting, helping to give a crunchy outer coating to the roast potatoes.
Also, as carrots are a hard root vegetable, they can be parboiled to soften them before being used in stir fry cooking, which is a rapid cooking technique.
It is different from blanching, as the ingredients are not shocked in cold or iced water.