Olfactory means relating to your sense of smell. Your olfactory system is the part of your body that detects and processes scents: from freshly baked cookies to wet dog to gasoline at a filling station.

When you breathe in, tiny particles from whatever you're smelling travel up your nose and touch special cells called olfactory receptors. These cells send signals to your brain, which figures out what you're smelling. This happens so fast you barely notice it.

Scientists who study smell talk about the olfactory bulb, the part of your brain that receives these smell signals. Some animals, like dogs and bears, have incredibly powerful olfactory abilities. A bloodhound's sense of smell is about 40 times stronger than yours, which is why they can track people through forests by following a scent trail you couldn't even detect.

Certain smells can trigger powerful memories because your olfactory system connects directly to the parts of your brain that store memories and emotions. That's why the smell of cinnamon might instantly remind you of your grandmother's kitchen, or why the scent of chlorine brings back memories of summer at the pool.