What does single mean?

Saylor has been asking for the meanings of a bunch of words, the one she asked about today was the word "single". I told her it meant just one. She started using it as I was getting dinner ready. She said "Beckam can have a single drink", "I'm going to take single more bite", and my favorite "I'm such a good single mom."!! I guess she has just heard that term before because I didn't give her that definition of single! She's so creative and smart and always keeps us laughing!