Explanation request for underscores _s theme responsive menu

Hello,

Could anyone please explain this line of code from the underscores (_s) theme:

<?php _e( ‘Menu’, ‘myThemeName’ ); ?>

I am trying to find a smoother solution for my responsive nav menu, but until i understand this line properly, i’m not sure if i can tweak this, or if i have to use a different solution.

What does the _e mean, in particular?

How does my theme name affect ‘Menu’ and is Menu an arbitrary word or something specific?

I know these are very elementary questions, but i’d be grateful for any insight anyone can offer.