Let me just add something.
"Boss" is very general name. You can use "bosu" to mean the highest person in a organization or a section.
If you want or need to specify, there are specific names for every different kinds of bosses like the ones Edson-san and alucky-san wrote.
Kakarichou, jichou, syachou, kachou, etc. are all one of the じょうしs for entry-level employees.