Cootie typically refers to a childish term for germs or a pretend illness spread among kids. It’s often used in games and social teasing, and also appears in folklore about imaginary infections. Key points

• Common meaning: a fictitious or minor contagious illness among children, often described as spread by close contact or by opposite-sex peers in playground lore.

• Historical context: the term entered English usage during the 19th and early 20th centuries and became associated with toys and games (e.g., The Game of Cootie) as well as wartime-era colloquialism.

• Modern usage: found in dictionaries as a playful or humorous reference to germs or disease, especially in American English.

• Related phrases: similar concepts exist in other cultures as “dreaded lurgi” or comparable kid-centric contagion myths.

If you’d like, I can tailor the explanation for a specific audience (e.g., kids, parents, educators) or provide examples of how the term is used in conversation.