diademyoudaoicibaDictYouDict
diadem: [13] A diadem was originally something that was bound round someone’s head. The word comes, via Old French diademe and Latin diadēma, from Greek diádēma; this was a derivative of diadein, a compound verb formed from the prefix dia- ‘across’ and dein ‘bind’. In Greek it was often applied specifically to the regal headband worn by Alexander the Great and his successors.
guitaryoudaoicibaDictYouDict
guitar: [17] The Greek kithárā was a stringed musical instrument of the lyre family, which has bequeathed its name to a variety of successors. Via Latin cithara came English citole [14], a medieval stringed instrument, and German zither (borrowed by English in the 19th century), while Arabic took it over as qītār and passed it on to Spanish as guitarra.

French adopted it in the form guitare (which eventually superseded the earlier guiterne), and it eventually reached English. (The history of guiterne, incidentally, is not entirely clear, although it is obviously a member of the kithárā family. English acquired it as gittern [14], applied to an early form of guitar, and it seems to have been blended with Latin cithara to produce English cithern or cittern [16], the name of a plucked stringed instrument of Renaissance times.)
=> zither
innyoudaoicibaDictYouDict
inn: [OE] An inn was originally literally a place one lived or stayed ‘in’. It comes from a prehistoric Germanic *innam, which was a derivative of the ancestor of the modern English adverb in, and in Old English it meant simply ‘house where one lives, abode, home’. This sense survived into the 17th century (‘Queen Mary gave this House to Nicholas Heth, Archbishop of York, and his successors for ever, to be their Inne or Lodging for their Repair to London’, James Howell, Londinopolis 1657), and a memory of it remains in London’s Inns of Court, which originated as lodgings for lawyers.

The later sense ‘public house, tavern’ developed towards the end of the 14th century.
=> in
diadem (n.)youdaoicibaDictYouDict
late 13c., from Old French diademe and directly from Latin diadema "cloth band worn around the head as a sign of royalty," from Greek diadema, from diadein "to bind across," from dia- "across" (see dia-) + dein "to bind," related to desmos "band," from PIE *de- "to bind." Used of the headband worn by Persian kings and adopted by Alexander the Great and his successors.
emperor (n.)youdaoicibaDictYouDict
early 13c., from Old French empereor "emperor, leader, ruler" (11c.; accusative; nominative emperere; Modern French empereur), from Latin imperiatorem (nominative imperiator) "commander, emperor," from past participle stem of imperare "to command" (see empire).

Originally a title conferred by vote of the Roman army on a successful general, later by the Senate on Julius and Augustus Caesar and adopted by their successors except Tiberius and Claudius. In the Middle Ages, applied to rulers of China, Japan, etc.; non-historical European application in English had been only to the Holy Roman Emperors (who in German documents are called kaiser), from late 13c., until in 1804 Napoleon took the title "Emperor of the French."
slave (n.)youdaoicibaDictYouDict
late 13c., "person who is the chattel or property of another," from Old French esclave (13c.), from Medieval Latin Sclavus "slave" (source also of Italian schiavo, French esclave, Spanish esclavo), originally "Slav" (see Slav); so used in this secondary sense because of the many Slavs sold into slavery by conquering peoples.
This sense development arose in the consequence of the wars waged by Otto the Great and his successors against the Slavs, a great number of whom they took captive and sold into slavery. [Klein]
Meaning "one who has lost the power of resistance to some habit or vice" is from 1550s. Applied to devices from 1904, especially those which are controlled by others (compare slave jib in sailing, similarly of locomotives, flash bulbs, amplifiers). Slave-driver is attested from 1807; extended sense of "cruel or exacting task-master" is by 1854. Slate state in U.S. history is from 1812. Slave-trade is attested from 1734.

Old English Wealh "Briton" also began to be used in the sense of "serf, slave" c.850; and Sanskrit dasa-, which can mean "slave," apparently is connected to dasyu- "pre-Aryan inhabitant of India." Grose's dictionary (1785) has under Negroe "A black-a-moor; figuratively used for a slave," without regard to race. More common Old English words for slave were þeow (related to þeowian "to serve") and þræl (see thrall). The Slavic words for "slave" (Russian rab, Serbo-Croatian rob, Old Church Slavonic rabu) are from Old Slavic *orbu, from the PIE root *orbh- (also source of orphan), the ground sense of which seems to be "thing that changes allegiance" (in the case of the slave, from himself to his master). The Slavic word is also the source of robot.

witch (n.)youdaoicibaDictYouDict
Old English wicce "female magician, sorceress," in later use especially "a woman supposed to have dealings with the devil or evil spirits and to be able by their cooperation to perform supernatural acts," fem. of Old English wicca "sorcerer, wizard, man who practices witchcraft or magic," from verb wiccian "to practice witchcraft" (compare Low German wikken, wicken "to use witchcraft," wikker, wicker "soothsayer").

OED says of uncertain origin; Liberman says "None of the proposed etymologies of witch is free from phonetic or semantic difficulties." Klein suggests connection with Old English wigle "divination," and wig, wih "idol." Watkins says the nouns represent a Proto-Germanic *wikkjaz "necromancer" (one who wakes the dead), from PIE *weg-yo-, from *weg- (2) "to be strong, be lively" (see wake (v.)).

That wicce once had a more specific sense than the later general one of "female magician, sorceress" perhaps is suggested by the presence of other words in Old English describing more specific kinds of magical craft. In the Laws of Ælfred (c.890), witchcraft was specifically singled out as a woman's craft, whose practitioners were not to be suffered to live among the West Saxons:
Ða fæmnan þe gewuniað onfon gealdorcræftigan & scinlæcan & wiccan, ne læt þu ða libban."
The other two words combined with it here are gealdricge, a woman who practices "incantations," and scinlæce "female wizard, woman magician," from a root meaning "phantom, evil spirit." Another word that appears in the Anglo-Saxon laws is lyblæca "wizard, sorcerer," but with suggestions of skill in the use of drugs, because the root of the word is lybb "drug, poison, charm." Lybbestre was a fem. word meaning "sorceress," and lybcorn was the name of a certain medicinal seed (perhaps wild saffron). Weekley notes possible connection to Gothic weihs "holy" and German weihan "consecrate," and writes, "the priests of a suppressed religion naturally become magicians to its successors or opponents." In Anglo-Saxon glossaries, wicca renders Latin augur (c. 1100), and wicce stands for "pythoness, divinatricem." In the "Three Kings of Cologne" (c. 1400) wicca translates Magi:
Þe paynyms ... cleped þe iij kyngis Magos, þat is to seye wicchis.
The glossary translates Latin necromantia ("demonum invocatio") with galdre, wiccecræft. The Anglo-Saxon poem called "Men's Crafts" has wiccræft, which appears to be the same word, and by its context means "skill with horses." In a c. 1250 translation of "Exodus," witches is used of the Egyptian midwives who save the newborn sons of the Hebrews: "Ðe wicches hidden hem for-ðan, Biforen pharaun nolden he ben." Witch in reference to a man survived in dialect into 20c., but the fem. form was so dominant by 1601 that men-witches or he-witch began to be used. Extended sense of "old, ugly, and crabbed or malignant woman" is from early 15c; that of "young woman or girl of bewitching aspect or manners" is first recorded 1740. Witch doctor is from 1718; applied to African magicians from 1836.
At this day it is indifferent to say in the English tongue, 'she is a witch,' or 'she is a wise woman.' [Reginald Scot, "The Discoverie of Witchcraft," 1584]