What is alone time?

I am married with a two yr old little boy, husband, and a 100 lb lab. I do not know the word of alone. I sometimes will try to stay up past everyone just so I can have some me time. My son is defiantly a momma's boy. He is always under my feet. I try so hard not to take it for granted. I just wanna bubble bath. I love to just relax and just be in the quiet. Not even do anything, just have the silence of the house around me.