/ˈraɪk/; German IPA: [ˈʁaɪç]), is a German loanword cognate with the English reign, region, and rich, but used most to designate an empire, realm, or nation. The qualitative connotation from the German is "imperial, sovereign state." It is cognate with the Scandinavian rike/rige, Dutch: rijk, Sanskrit: raj, English: -ric; as found in bishopric. It is the word traditionally used for a variety of sovereign entities, including Germany in many periods of its history. It is also found in the compound Königreich, "kingdom" (Königtum), and in the country names Frankreich (France, lit. "the Realm of the Franks"), Österreich (Austria, the "Eastern Realm"), Sverige (Sweden, the "Realm of the Swedes") and in England as Surrey - Suthrige, 'southern realm'. The German version of the Lord's Prayer uses the words Dein Reich komme for "ἐλθέτω ἡ βασιλεία σου" (usually translated as "thy kingdom come" in English), and the Lord's Prayer in Scandinavian also uses the cognate word; so it is in Old English - 'Tobecyme thin rice'.(IPA:
Used adjectivally, reich is the German word for "rich". Like its Latin counterpart, imperium, Reich does not necessarily connote a monarchy; the Weimar Republic and Nazi Germany continued to use the name Deutsches Reich.
Rike is the Swedish and Norwegian word for "realm", in Danish spelled rige, of similar meaning as German Reich. The word is traditionally used for sovereign entities; a country with a King or Queen as head of state, such as the United Kingdom or Sweden itself, is a (kunga)rike, literally a "royal realm".
The word is used in "Svea rike", with the current spelling Sverige, the name of Sweden in Swedish. The derived prefix "riks-" implies nationwide or under central jurisdiction such as in riksväg, the Swedish name for federal road. It is also present in the names of institutions such as the Riksdag, Sveriges Riksbank, Riksåklagaren, Rikspolisstyrelsen, Riksteatern, riksdaler, etc.
The Lord's Prayer uses the words in the Swedish version — Tillkomme ditt rike (Thy kingdom come).
Rijk is the Dutch equivalent of German Reich. In a political sense in the Netherlands the word rijk often connotates a connection with the Kingdom of the Netherlands; the ministerraad is the executive body of the Netherlands' government and the rijksministerraad that of the Kingdom of the Netherlands, a similar distinction is found in wetten (laws) versus rijkswetten (kingdom laws). The word rijk can also be found in institutions like Rijkswaterstaat, Rijksinstituut voor Volksgezondheid en Milieu, and Rijksuniversiteit Groningen.
Like in German, the adjective rijk means "rich".
 Etymology and cognates
Reich comes from a Germanic word for "king", which was borrowed from Celtic. (See Calvert Watkins, American Heritage dictionary of Indo-European Roots, p.70.) It has cognates in many other languages, all ultimately descended from the Proto-Indo-European root *reg-, meaning "to straighten out" or "rule", also the source of English right. The Sanskrit derived cognates in Hindi are "Raja" meaning King and also the name of an ethnic group: Rajput meaning progeny of Rajas. The cognates can be grouped linguistically as follows:
 Celtic group
- Various Celtic words for "king" including Gaelic righ.
- Borrowed into Germanic as *rīks-. Hence:
- Old High German: richi; German: Reich (all senses); Reichtum "riches"; but not the unrelated verb reichen, "to reach", or its derivative Bereich, "subject area, sphere".
- Old English: rīce; Modern English: rich.
- Dutch: rijk
- Danish: rige (as in Rigsmal)
- Swedish and Norwegian: rike (as in Riksmål; Sverige, "Sweden").
- Old Norse and Icelandic: ríki (as in Garðaríki).
- Many Germanic names (personal names), including Friedrich, Dietrich and Richard.
- Borrowed from Germanic:
- French: riche (borrowed from Germanic)
- Old Prussian: reiks (borrowed from Germanic)
- Spanish: rico, "rich" (borrowed from Gothic)
- Lithuanian: rikė
- Various Slavonic words borrowed from Germanic, all loaned from Old High German dialects and include Slavonic phonetic innovations (like the change from r into ř-sound and soft Germanic "ch" into Slavonic "š" (like the "sh" in "she"). The PIE root "*reg-" (rule) is non-existent in Slavonic. There is also no native Slavic root for "king" and "kingdom" or similar words, probably because the early Slavic societies were highly democratic and ruled by an ancient form of parliament "wiec". Hence, Slavonic words generally meaning "king" derive from the name of Charlemagne in Old French, "Karol". Similarly, the words that mean more or less the aristocratic title "prince" come from Gothic "kunings" (with many local phonetic changes, e.g. "knędz" in Old Polish, "książę" in Polish and "kniaz'" in Ruthenian).
- Polish: rzesza - nowadays often associated with "Trzecia Rzesza" (The Third Reich) in colloquial speech; second meaning: "a great group of people, throng, mob"
- Czech: říše
- Slovak: ríša
 Original Germanic group
Although the line of descent of Reich and its closest cognates came into Germanic sideways from Celtic, Germanic also inherited the same Indo-European root directly in a suffixed form of the e-grade, *reg-to-, hence:
- Old High German: rihte; Modern German Recht, "justice"; rechts, "right"; richtig, "correct"; Richter, "judge"; Gericht, "court".
- Old English: riht; Modern English: right; righteous.
The basic e-grade form of the root came into Latin as: regere (supine stem rectus), "to rule"; rex, regis, "king"; regalis, "kingly". A suffixed, lengthened e-grade form, *rēg-ola- gives us Latin regula, "rod". Hence:
- French: roi "king", droit "law, right" and many others.
- Spanish: rey "king"
- Portuguese: rei "king"
- German: regieren "to govern, to rule", Regierung "government", Regel "law, rule"
- English (straight from Latin): regent; regal; regulate; rector; rectangle; erect; (borrowed via French): royal, reign; viceroy; realm; ruler (both senses) and countless others.
The Sanskrit word, from a lengthened-grade suffixed form *rēg-en-, is rājā, "king", hence the words for rulers in various Indian languages. Of interest to English speakers: Raj, used of the British rule in India; and Maharaja, literally "the great king" (exactly parallel to Latin magnus rex).