substract (v.)youdaoicibaDictYouDict[substract 词源字典]
"to subtract," 1540s, "now illiterate" [OED], "An erroneous form of subtract, common in vulger use" [Century Dictionary], from Modern Latin substractus, past participle of substrahere, alternative form of subtrahere (see subtraction). Related: Subtracted; subtracting.[substract etymology, substract origin, 英语词源]