everywhere i read about secret societies, secret millitary bases, secret  here secret there

my understanding of the wrd secret describes something not everyone knows

but when i google skul and bones it says its a secret society, how can it be secret if its listed on google

the same with area51, how is area51 any secret when everyone talks about it

is the word secret just a way to promote something that otherwise noone would be interessted in

can someone explain that??