來自古法語 salpetre,硝石，硝酸鉀，來自拉丁語 sal petrae,石頭上的鹽，來自 sal,鹽，詞源同 salt,petra,石頭，詞源同 petrous,petrol.因這種物質形如鹽在石頭上的結晶體而得名。
英文詞源
saltpeter (n.)
"potassium nitrate," c. 1500, earlier salpetre (early 14c.), from Old French salpetre, from Medieval Latin sal petrae "salt of rock," from Latin sal "salt" (see salt (n.)) + petra "rock, stone" (see petrous). So called because it looks like salt encrusted on rock.