The only free and comprehensive online etymological dictionary of the Spanish language
sumo (1) (Adjective) "supreme"
10th cent. Old Spanish somo "highest," which is preserved in the archaic phrase en somo "in total." From Latin summus "highest." From Proto-Italic *sup(a)mo-'id.' From Proto-Indo-European *(h1)up-m̥(H)o- 'id.'
Indo-European
Romance
Portuguese sumo, Italian sommo
Italic
Umbrian sume "highest (place)"
Germanic
Gothic auhuma "highest," Old English yfemest 'id.'
Indo-Iranian
Sanskrit upama "uppermost"
sumo (2) m. (Noun) "sumo wrestling;" "sumo wrestler"
From Japanese sumō "sumo wrestling," but lit. "to rush at."
sumo (3) m. (Noun) "Sumo language family;" "Sumuic language"
Name for a branch of the Misumalpan languages, spoken in Nicaragua and Honduras.
sumo (4) m. (Noun) "juice"
Borrowed from Old Portuguese çumo 'id.,' which was borrowed from Arabic zūm 'id.' (see zumo).
suponer (Verb) "to suppose"
From sub- "under" (see so) and poner.
sur m. (Noun) "south"
Late 15th cent. Borrowed from French sud 'id.,' itself borrowed from Old English suþ 'id.'
sur-, sobre- (Prefix) "over"
Prefix sobre- is from Latin super- 'id.,' from the preposition super. Prefix sur- is from Latin sur-, a syncopation of super-. See sobre.
susto m. (Noun) "scare," "fright"
Very early 17th cent. Of unknown origin.
suyo (Personal Pronoun) "(of) his;" "(of) hers;" "(of) theirs;" "(of) yours"
Old Spanish súo. From Latin suus 'id.' From Proto-Italic *sowós. From Proto-Indo-European *seu̯ós 'id.,' from *su̯e "self" (whence se).
"This word *swe has given rise to an adjective indicating “personal belonging”: Skt. sva-, Lat. suus, Gr. *swós (*σwός). We must note that *swos is not in Indo-European the pronoun of the third person singular, as might be supposed by the relation of Lat. suus to meus and tuus. We instinctively make suus the third term of the series. Just as we put I, you, he in the verbal inflexion, it seems normal to us to have the pronominal series my, your, his. The relationship of these forms was quite different in Indo-European: *swos is the reflexive and possessive pronoun equally applicable to all persons." ~ E. Benveniste, Indo-European Language and Society (1973)