"Ke family" refers to a group of words in the Mandarin Chinese language that all have the same sound at the end of the word, which is "ke". It's like a group of friends who all have the same last name, but instead of being people, they are words!
Some words in the "ke family" include: 窠客 (kē), which means "nest", 渴 (kě), which means "thirsty", 客 (kè), which means "guest", and 可 (kě), which means "can" or "able".
When you're learning Chinese, it can be helpful to know which words are in the same "family" because they likely share similar sounds and tones. Plus, it's just kind of fun to recognize and remember these groups of words!