el tramézashíël eslévár (n.): Empire of the Star; the largest and oldest eldraeic polity.
Broken up, this phrase reads: tra (DESCRIPTION OPERATOR) – méz (METAPHORIZATION OPERATOR) – ashíël (star) — eslév (empire) – ár (PREDICATION OPERATOR), which is to say in long-gloss, “the empire which is like unto a (metaphorical) star”. Replacing this with the English “of” is acceptably inaccurate for such an imprecise target language.
It should also be noted that eslév is linguistically unique, appearing only in this phrase (and abbreviations thereof: el eslév unambiguously refers to “the Empire”). It is not used to represent any of the other possible meanings of “empire”; the technical meaning of a union of multiple peripheral polities beneath one metropole, for example, is el vielmóniramóníë (loosely, “a commanding country-of-countries”).
It has no strict root-based etymology; rather, eslév is a nonce coined for its conceptual resonances: it resembles, for example, proto-Cestian words for “created” or “our creation”; Selenarian terms for “lunar crescent”; various Silver Crescent words with meanings approximating to “celestial”; a Veranthyran term meaning “propriety” or “high culture”, and so on and so forth.