The only free and comprehensive online etymological dictionary of the Spanish language
pasar (Verb) "to pass"

12th cent. From Vulgar Latin *passare 'id.,' from Latin passus "step" (see paso).

Pasenle "enter," primarily found in unwritten Mexican Spanish, formed from the imperative and le. See note under andar for more information.
pasear (Verb) "to walk"

15th cent. From paso.
paseo m. (Noun) "walk"

Very early 17th cent. Derived from pasear.
paso m. (Noun, Adjective) "step;" "way"

13th cent. From Latin passus 'id.' From Proto-Italic *patto- 'id.' A past participle of Proto-Indo-European *peth2- "to extend," "to spread out," which later acquired the sense of walking.
pasta f. (Noun) "pasta"

13th cent. From Latin pasta "paste," borrowed from Ancient Greek πάστα ‎(pásta) 'id.,' probably from παστός (pastós) "strewn." Of unknown origin.
pastel m. (Noun) "cake"

Late 15th cent. Borrowed from French pastel 'id.,' itself borrowed from Italian pastello "dough." Taken from Medieval Latin pastellum 'id.,' from Latin pasta "paste" (see pasta).
paz f. (Noun) "peace"

12th cent. From Latin pax 'id.' From Proto-Italic *pāk- "agreement." From Proto-Indo-European *peh2ḱ-

Romance: Western Vulgar Latin: Asturian paz, Portuguese paz, Galicianpaz, Catalan pau, French paix, Italian pace ; Eastern Vulgar Latin: Romanian pace ; Sardinian: pache

Italic: Umbrian pacer "peace," Marsian pacre 'id.,' Paelignian pacrid "by peace"

Indo-European: Germanic: Gothic fagrs "fit," Old Norse fagr "beautiful," Old High German fuogen "to join," Old Saxon fōgian 'id.,' Old English fēgan 'id.' (English to fay); Hellenic: Attic Greek πήττω (pétto) "I join;" Indo-Iranian: Sanskrit pā́śa- "snare," Khotanese pāsa- "cord;" Anatolian: Hittite pāški "to fasten"
pecho m. (Noun) "breast," "chest"

12th cent. From Latin pectus 'id.' From Proto-Italic *pektos- 'id.' Of unknown origin. The cognate in Old Irish ucht "breast" suggests that this is either a mutual innovation or cognate loanword from an outside source within the Italo-Celtic subgroup.

Romance: Western Vulgar Latin: Asturian pechu, Portuguesepeito, Galician peito, Catalan pit, French pis, poitrine, Italian petto ; Eastern Vulgar Latin: Aromanian cheptu, Romanian pet ; Sardinian: petus

Celtic: Old Irish ucht "breast" (fextu- pektu-)
pedazo m. (Noun) "piece"

12th cent. Old Spanish pedaço. From Vulgar Latin petaccium 'id.,' from Latin pitaccium "piece (of cloth)." Borrowed from Ancient Greek πιττάκιον ‎(pittákion) "scrap (of garment);" "tablet;" "note." Of unknown origin.

Romance: Western Vulgar Latin: Asturian pedazu, piozu, Portuguese pedaço, Catalan pedaç, Italian petacciola
pedir (Verb) "to request"

12th cent. From Latin petere "to seek." From Proto-Italic *pet-e/o- 'id.' Perhaps from Proto-Indo-European *pt-i̯ "to fly (towards)," but the sense evolution is obscure.

Romance: Western Vulgar Latin: Portuguese pedir ; Eastern Vulgar Latin: Romanian peți ; Sardinian: pedire

Italic: Venetic ekvopetaris? "of a horse-rider"