Anglo-SaxonyoudaoicibaDictYouDict[Anglo-Saxon 词源字典]
Old English Angli Saxones (plural), from Latin Anglo-Saxones, in which Anglo- is an adjective, thus literally "English Saxons," as opposed to those of the Continent (now called "Old Saxons"). Properly in reference to the Saxons of ancient Wessex, Essex, Middlesex, and Sussex.
I am a suthern man, I can not geste 'rum, ram, ruf' by letter. [Chaucer, "Parson's Prologue and Tale"]
After the Norman-French invasion of 1066, the peoples of the island were distinguished as English and French, but after a few generations all were English, and Latin-speaking scribes, who knew and cared little about Germanic history, began to use Anglo-Saxones to refer to the pre-1066 inhabitants and their descendants. When interest in Old English writing revived c. 1586, the word was extended to the language we now call Old English. It has been used rhetorically for "English" in an ethnological sense from 1832, and revisioned as Angle + Saxon.[Anglo-Saxon etymology, Anglo-Saxon origin, 英语词源]
ethnology (n.)youdaoicibaDictYouDict
"science of the characteristics, history, and customs of the races of mankind," 1832, from ethno- + -logy, perhaps modeled on French or German. Related: Ethnologist; ethnological.
Ethnology is a very modern science, even later than Geology, and as yet hardly known in America, although much cultivated latterly in Germany and France, being considered an indispensable auxiliary to history and geography. ["Atlantic Journal and Friend of Knowledge," Philadelphia, summer 1832]
TartaryoudaoicibaDictYouDict
mid-14c. (implied in Tartary, "the land of the Tartars"), from Medieval Latin Tartarus, from Persian Tatar, first used 13c. in reference to the hordes of Ghengis Khan (1202-1227), said to be ultimately from Tata, a name of the Mongols for themselves. Form in European languages probably influenced by Latin Tartarus "hell" (e.g. letter of St. Louis of France, 1270: "In the present danger of the Tartars either we shall push them back into the Tartarus whence they are come, or they will bring us all into heaven").

The historical word for what now are called in ethnological works Tatars. A Turkic people, their native region was east of the Caspian Sea. Ghengis' horde was a mix of Tatars, Mongols, Turks, etc. Used figuratively for "savage, rough, irascible person" (1660s). To catch a Tartar "get hold of what cannot be controlled" is recorded from 1660s; original sense not preserved, but probably from some military story similar to the old battlefield joke:
Irish soldier (shouting from within the brush): I've captured one of the enemy.
Captain: Excellent! Bring him here.
Soldier: He won't come.
Captain: Well, then, you come here.
Soldier: I would, but he won't let me.
Among the adjectival forms that have been used are Tartarian (16c.), Tartarous (Ben Jonson), Tartarean (17c.); Byron's Tartarly (1821) is a nonce-word (but a good one). Tartar sauce is first recorded 1855, from French sauce tartare.