F A C E B O O K U N B L O C K E R What Are The Sign A,b,c,d,e,f,g,h,i,j,k,l,m,n,o,… Means In Physics?

What are the sign a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,… means in physics? - f a c e b o o k u n b l o c k e r

I have a job, and said that my roof will help the significance of the letter of each sign, please find me with my homework ..

thanks ..