Hi Armani Kramer,
 
Thanks for reaching out.
 
The R squared was introduced in Lecture 193. It is the measure of variability of the data explained by the model. The nearer it is to 1, the better is the fit of the model to the data being estimated. For R-square equal to 0.88 (or 88%) it implies that 88% variability in Y is explained by the model with the independent variables in it. This is a good number for R-square.
 
Hope this helps.
Best,
The 365 Team