verb
chats; chatted; chatting
[no obj]
to talk with someone in a casual way
to talk over the Internet by sending messages back and forth in a chat room
chat up
[phrasal verb]
chat (someone) up or chat up (someone) informal :to talk informally with (someone, such as someone you are attracted to)
noun
plural chats
[count] :a light and friendly conversation
a talk held over the Internet by people using a chat room [count]
US