Generally, bushi refers to 'a service member who is a master of military art and battle or a military strategist,' but by this definition, the difference between the 'military officer' under the Ritsuryo system (a system of centralized government based on the ritsuryo code) before the Heian period and the bushi is not clear.
武士は、一般に「武芸に通じ、戦闘を職業とする軍人、あるいは兵法家のこと」とされるが、これだけでは平安時代以前の律令制体制下の「武官」との違いがはっきりしない。