To hug someone is to warmly embrace or grasp them with your arms. Some families hug each other all the time, while others save their hugs for special occasions.
Celebrate National Hug Your Cat Day if you want to, but your cat may be less enthusiastic about it than you are. Hug is both a verb and a noun: when you hug your cat, she gets a hug. You can also hug your knees, holding them close to your body, and your skinny jeans can be said to hug your legs, or fit tightly. Hug probably comes from the Old Norse hugga, "to comfort."