The only free and comprehensive online etymological dictionary of the Spanish language
rápido (Adjective) "quick"
A 17th cent. learned borrowing from Latin rapidus "quick," but literally "seized," an adjective from rapere "to snatch" (see raptar), which replaced the Old Spanish adverb aína.
Indo-European
Romance
Asturian rápidu, Portuguese rápido, French rapide, Italian rapido, Romanian rapid
Corominas (1991) notes that rápido cannot have been borrowed earlier than the 17th cent., as the Spanish-Italian dictionary Vocabulario de las dos lenguas Italiano y Castellano by Cristóbal de las Casas (c. 1570) translates the Italian rapido as "arrebatado, ligero" and not as "rápido."
raptar (Verb) "to kidnap"
Early 20th cent. borrowing from Latin raptare "to kidnap," a verb formed from raptus "seized," the passive participle of rapere "to snatch," "to kidnap." From Proto-Italic *rap-i- 'id.' From Proto-Indo-European *h1rp-i̯- 'id.'
Indo-European
Romance
Portuguese raptar
Albanian
Albanian rjep "to tear off"
Balto-Slavic
Lithuanian ap-rė́pti "to take"
Hellenic
Ancient Greek ἐρέπτομαι (eréptomai) "to devour"
raro, ralo (Adjective) "strange;" "rare"
14th cent. Old Spanish ralo; very late 15th cent. raro. The intervocalic dental was uncertain, curiously leading to two native reflexes of the same Latin word. Raro and ralo were free variants until Modern Spanish and never distinctly separate. From Latin rarus "scattered," "rare," "thin." Of unknown origin.
Indo-European
Romance
Asturian ralu, raru, Portuguese ralo, raro, Galician raro, Catalan rar, French rare, Italian raro, Aromanian rar, Romanian rar, Sardinian raru
rastrillo m. (Noun) "rake;" "comb"
Very late 15th cent. Old Spanish rastrillo, rastillo. From Latin rastellus 'id.,' dimunitive of rastrum "rake" (see rastro).
rastro m. (Noun) "rake;" "sign;" "market;" "trail"
11th cent. From Latin rastrum "rake." From radere "to scrape (see raer) and instrumental noun-forming suffix -trum (see -tro).
The meaning of "market" comes from the name of el Rastro, a market located in Madrid. The origin of its name is uncertain, although the traditional theory is that it was so-called because of a rastro ("trail") of blood flowing from recently-slaughtered cattle who were brought to market.
Indo-European
Romance
Portuguese rastro, Galician rastro, Catalan rastre, Italian rastro, Romanian rastru
"Díxose Rastro porque los llevaban arrastrando, desde el corral a los palos donde los degüellan, y por el rastro que dexan se le dio este nombre al lugar." ~ Covarrubias, El tesoro de la lengua castellana o española (1611)
rata (1) f. (Noun) "rat"
13th cent. From Vulgar Latin *ratta 'id.' Borrowed from Proto-West Germanic or Proto-Germanic *ratta- 'id.' According to Kroonen (2011), a pre-form *Hrót-ēn- is reconstructible, but ultimately of unknown origin.
Indo-European
Germanic
Old High German ratto "rat," Old Saxon ratta 'id.,' English rat
rata (2) f. (Noun) "proportional part"
13th cent. From Latin rata, feminine of ratus "established." From Proto-Italic *rato- "thought." From Proto-Indo-European *Hr̥h1-to- "counted."
Indo-European
Germanic
Gothic raþjo "number," Old High German redea "account," Old Saxon rethia 'id.'
rato (1) m. (Noun) "brief time;" "moment"
13th cent. From Latin raptus "carried (away)." From rapere "to seize" (see raptar).
Indo-European
Romance
French rapt
rato (2) (Adjective) "confirmed"
From Latin ratus "established." From Proto-Italic *rato- "thought." From Proto-Indo-European *Hr̥h1-to- "counted."
Indo-European
Germanic
Gothic raþjo "number," Old High German redea "account," Old Saxon rethia 'id.'
rayo m. (Noun) "ray"
13th cent. From Latin radius 'id.' Of unknown origin.
Indo-European
Romance
Portuguese raio, Catalan raig, French rai, Italian raggio, Aromanian radzã, Romanian rază, Sardinian ragiu