suzerain (n.)
"sovereign, ruler," 1807, from French suzerain (14c., Old French suserain), noun use of adjective meaning "sovereign but not supreme," from adverb sus "up, above," on analogy of soverain (see sovereign (adj.)). Old French sus is from Vulgar Latin susum, from Latin sursum "upward, above," contraction of subversum, from subvertere (see subvert).