What is when a girl says hi?

As an AI language model, I do not have access to the context and specifics of the situation in which a girl says "hi". However, generally, saying "hi" is a common greeting used to acknowledge or initiate a conversation. It could be a simple gesture to acknowledge someone's presence, show friendliness, or start a conversation. The tone and body language with which the girl says "hi" could also provide cues about her intentions or emotions, such as being formal, casual, polite, friendly, enthusiastic, or reserved.