To partially cook food, usually vegetables or fruit, in boiling water or steam. Immediately after blanching, vegetables are usually placed in ice water to stop the cooking and set the color.
to partially cook raw ingredients (usually fruit or vegetables) in boiling water briefly ... more on blanche here
Blanching is a process in which food is briefly plunged in boiling water for a moment, then immediately transferred to ice water to stop the cooking process. Blanching tomatoes or peaches for about 20 seconds makes them easier to peel. Vegetable Freezing Guide