The only free and comprehensive online etymological dictionary of the Spanish language
diestro (Adjective) "right (side);" "skillful"
12th cent. From Latin dexter 'id.' From Proto-Italic *deks-tero- "right (side)." From Proto-Indo-European *deḱs-tero- 'id.' The first element is from *deḱos "proper;" the second element is the comparative suffix *-tero- (see -tr-). Proto-Indo-European *deḱos is from *deḱ- "to accept," "to perceive."
Indo-European
Romance
Asturian diestru, Portuguese destro, Catalan destre, French dextre, Italian destro
Italic
Oscan destrst, Umbrian destre "on the right"
Celtic
Old Irish dess, Middle Welsh deheu, Breton dehou, Middle Cornish dehow
Germanic
Gothic taihswa, Old Saxon tesewa, Old High German zeso
Albanian
Albanian djathtë
Balto-Slavic
Old Church Slavonic desnъ, Lithuanian dẽšinas
Hellenic
Ancient Greek δεξιϝος (deksiwos), Mycenaean de-ki-si-wo,
Indo-Iranian
Sanskrit dákṣina-
diez (Cardinal Number) "ten"
12th cent. From Latin decem. From Proto-Italic *dekm̥ 'id.' From Proto-Indo-European *deḱm̥ 'id.'
Indo-European
Romance
Asturian diez, Portuguese dez, Galician dez, Catalan deu, French dix, Italian dieci, Aromanian dzatsi, Romanian zece, Sardinian dèke
Italic
Oscan δεκμας (dekmas) "tithe"
Celtic
Celtiberian tekametam- "tenth," Gaulish decametos "tenth," Old Irish deich, Middle Welsh deg, Old Breton dec, Old Cornish dec
Germanic
Gothic taihun, Old Norse tíu, Old High German zehun, Old Saxon tehun, Old English tīen (English ten)
Balto-Slavic
Old Church Slavonic desętь, Lithuanian dẽšimt
Hellenic
Ancient Greek δέκα (déka)
Armenian
Armenian tasn
Indo-Iranian
Sanskrit dáśa, Young Avestan dasa
Tocharian
A śäk, B śak
diferencia f. (Noun) "difference"
13th cent. From Latin differentia 'id.,' derived from differens "different" (see diferente).
diferente (Adjective) "different"
Late 15th cent. From Latin differentem, accusative of differens 'id.,' from the verb differre (see diferir).
Indo-European
Romance
Asturian diferir, Portuguese diferir, Galician diferir, Catalan diferir, French différer, Italian differire, Romanian diferi
diferir (Verb) "to differ"
15th cent. From Latin differre 'id.,' from dis- "away" and ferrer "to support" (see dis- and fértil respectively for continued etymologies).
difícil (Adjective) "difficult"
From Latin difficilis 'id.,' from dis-, a negating prefix, and facilis "easy" (see dis- and fácil respectively).
Indo-European
Romance
Asturian difícil, Portuguese difícil, Galician difícil, Catalan difícil, French difficile, Italian difficile
difundir (Verb) to diffuse, "to spread"
16th cent. From Latin diffundere 'id.,' from dis- "apart" and fundere "to pour." See dis- and hundir respectively.
Indo-European
Romance
Portuguese difundir, Galician difundir, Catalan difondre, Italian diffondere
dinero m. (Noun) "money"
11th cent. From Latin denarius, a silver coin valued at 10 as (meaning literally "containing ten"). From deni "tens," "ten each" and -arius, agent-forming suffix (see -ero). Latin deni is from Proto-Italic *dekeni "tens." A plural of Proto Indo-European *deḱm̥ "ten" (see diez).
Indo-European
Romance
Asturian dineru, Portuguese dinheiro, denário, Galician diñeiro, Catalan diner, denari, French denier, Italian denaro, danaro
dios m. (Noun) "god"
10th cent. From Latin deus 'id.,' from Old Latin deiuos. From Proto-Italic *deiwo- 'id.' From Proto-Indo-European *dei̯-u̯-o- 'id.' From earlier *di̯-eu̯-, the name of the Indo-European sky god. See also día.
Indo-European
Romance
Asturian dios, Portuguese deus, Galician deus, Catalan déu, French dieu, Italian dio, Romanian zeu, Sardinian déu
Italic
Oscan διωϝηις (dioweis), Umbrian di "Zeus!," Pre-Samnite δι- (di-), Marrucinian ioues, Paelignian iouiois "to the gods," Marsian iouies 'id.'
Celtic
Old Irish dïe "day," Old Welsh did 'id.,' Old Breton ded 'id.,' Old Cornish det 'id.'
Germanic
Old Norse Týr "Tyr," Old English Tiw (English Týr, Tuesday)
Balto-Slavic
Old Church Slavonic dьnь "day," Lithuanian diẽvas, Old Prussian deiwas
Hellenic
Ancient Greek Zεύς (dzeys) "Zeus," Mycenaean di-we
Messapian
Messapian zis "Zeus"
Armenian
Armenian tiw
Indo-Iranian
Sanskrit devá- "god," Old Avestan daēuua- "god (of the pre-Zoroastrian peoples)"
The expected evolution of Latin into Spanish would have been **dio. Perhaps -s was conserved due to the important role of the word and its frequent use.
dirección f. (Noun) "direction;" "address"
Early 17th cent. From Latin directionem, an accusative past participle formed from the verb dirigere "to direct" (see dirigir).