The word mold has two completely different meanings:

1. A hollow container used to give shape to something poured or pressed into it. Bakers use cake molds to create fancy shapes. Factories use molds to make identical plastic toys by pouring hot plastic into the same shape thousands of times. You can make ice cubes in a mold, or use a sand mold at the beach to build a castle tower. The verb form means to shape something this way: a sculptor might mold clay into a bowl.
2. A fuzzy growth that appears on old food, damp walls, or wet surfaces. Mold is actually a type of fungus (related to mushrooms) that spreads by releasing tiny spores into the air. You might see green or black mold on forgotten bread in the back of the pantry, or white mold on cheese left too long in the refrigerator. While some molds help make foods like blue cheese or penicillin medicine, others can make people sick or damage buildings, so it's important to keep things dry and throw away moldy food.

The verb mold can also mean to influence how something or someone develops, like how a great teacher molds young minds or how experiences mold your character over time.