Hi Nana, I think they are "abbreviations"..They can't be labelled suffixes because a suffix is an affix that is added to the end of a word that conditions its usage or meaning. here is an example of suffixes : suffix "cide", its meaning: murder, killing agent , example of words: suicide , vespacide, regicide...

Jr = junior (ie. the younger) Sr = senior (ie. the older) This is used in rich families which have a tradition of naming the son after the father. For example, both father and son may have the same name: Maxwell Houseworth. Maxwell Houseworth Sr is the father. Maxwell Houseworth Jr is the son.