Smell is one of your five senses, the ability to detect odors through your nose. When you smell something, tiny molecules from that thing float through the air and reach special sensors inside your nose, which send signals to your brain. That's how you know when cookies are baking, when something's burning, or when it's time to take out the garbage.

Smell works closely with taste: most of what you think you're tasting is actually smell. Try holding your nose while eating an apple and an onion. They'll taste surprisingly similar! Your nose does most of the work in detecting flavors.

The word also means an odor itself. A bakery has a wonderful smell. A gym might have an unpleasant smell. Some smells are faint and require you to get close, while others are so strong they fill an entire room.

As a verb, smell can mean to use your nose deliberately: you might smell the milk to check if it's still good, or smell a flower in the garden. When something smells, it gives off an odor, whether pleasant or not. Your dog might smell terrible after rolling in mud, or your grandmother's kitchen might smell amazing when she's cooking.

Scientists have found that smell connects powerfully to memory. A particular scent can instantly transport you back to a specific moment, like smelling crayons and suddenly remembering kindergarten.