The word chellam is used to call our dear ones whom we don't want to miss. There is nothing like only a particular relationship should use this.
Practice makes perfect..
The word Chellam is very famous in Tamil. The word Chellam got more famous by the tamil film "KILLI" in which Mr.Prakash Raj used the word Chellam frequently to call his lover. There is no exact meaning for the word chellam in tamil.
We can assume that the word chellam to call the person that we are having more affection on them whether the person is either male or female. Some peoples are using the word chellam to call the children with affection.
There is even a film in tamil itself named "Chellam" for a bit of additional information.
the word cheellam is a pet name in tamil.
this is similiar to the word darling in english.
few people use this word instead of dear also.
chellam is a tamil word that used to call your friends, girl friend, boy friend, son, daughter, wife, lover to make them happy.This word deliver their affection to their dear one. Everyone needs someone to call by this word. In Hindi you may heard about the word yaar its similar to like that. You can use this word who ever you like. When you use this word it makes them happy.