Research on social presence and online learning continues to grow. But   to   date,   researchers   continue   to   define   and   conceptualize   social  presence  very  differently.  For  instance,  at  a  basic  level,  some  conceptualize  social  presence  as  one  of  three  presences  within  a  Community of Inquiry, while others do not. Given this problem, we analyzed  how  researchers  in  highly  cited  social  presence  research  defined social presence in an effort to better understand how they are  defining  social  presence  and  how  this  might  be  changing  over  time. In this article, we report the results of our inquiry and conclude with implications for future research and practice.