1. To a small extent.
2. Only to a small extent; not much or often (used for emphasis).
3. Small in size, amount, or degree (often used to convey an appealing diminutiveness or express an affectionate or condescending attitude).
4. Denoting something, especially a place, that is the smaller or smallest of those so named or is named after a similar larger one.
You're going to have a little brother or sister.