To keep means to have and hold on to something — like to keep your wallet in your pocket. It also means to continue; if you keep hula hooping you’ll break the world record!
Keep has many senses in English, and shows up in a lot of our common expressions, like “keep out!" and "keep your shirt on!" The word generally has the senses of hold onto, maintain, stay, continue, or protect from harm. Food that will not spoil yet will keep. You can keep a secret, keep a diary, or keep your little sister safe. You can also keep a ritual or religious custom by practicing it –- like to keep kosher. Whatever you do, “just keep going.”