<p>Yeah, as people mentioned
There are three types of applications (for early)</p>
<p>Early Action: Non-Binding (you don’t have to go if they accept you) + You can apply to as many as you want. MIT and Caltech fall under this category. If you do this, you cannot apply for single choice early action, but you can do 1 early decision school in addition to your early actions.</p>
<p>Single-Choice Early Action: Non-Binding (you don’t have to go if they accept you), but you can only apply to the SCEA school and no others, meaning if you apply for SCEA at Stanford, you cannot apply early action to any other school or early decision. As far as I know, only Stanford and Yale do this.</p>
<p>Early Decision: Binding(you have to go if they except you, unless extreme financial/family circumstances arise) and you can apply to as many regular EA colleges, but not an SCEA. Penn falls into this category.</p>