Blanching. Plunging an ingredient (usually vegetables) into boiling salted water for a very short time (a few seconds), and then into very cold water.
Example: "Blanch the green beans." Meaning: Bring a large pan of water to the boil, tip in green beans for one minute, remove with a strainer and put into very cold water (if possible with ice cubes). Leave to cool then drain.
This is ofen done to preserve the couleur of the ingredient in the final dish.