The 'samurai' were the original bushi in a narrow sense, had shoryo (chigyo [enfeoffment]) and when the war happened he rode on a horse and had the entitlement of 'omemie' ([the privilege to have] an audience [with one's lord, a dignitary, etc.]).
「侍」は狭義の、つまり本来の武士であり、所領（知行）を持ち、戦のときは馬に乗る者で「御目見え」の資格を持つ。