"偵探，職業是調查需要信息的事情，特別是關於罪犯，並獲取對他們的證據"，1828年，縮寫自 detective police，來自 detective（形容詞）"適合或擅長偵查"（在1828年之前）； 參見 detect + -ive。
His duties differ from those of the ordinary policeman in that he has no specific beat or round, and in that he is concerned with the investigation of specific cases, or the watching of particular individuals or classes of offenders, rather than with the general guardianship of the peace, and does not wear a distinguishing uniform. [Century Dictionary, 1897]
他的職責與普通警察不同，因爲他沒有特定的巡邏區域，他關注的是特定案件的調查，或者是特定個人或類別的罪犯的監視，而不是一般的維護和平，也不穿着有區別的制服。[世紀詞典，1897年]
