The only free and comprehensive online etymological dictionary of the Spanish language
absoluto (Adjective) "absolute"

15th cent. From Latin absolutus "concluded," "unrestricted." From absolvere "to absolve," "to loosen." See absolver.

Romance: Western Vulgar Latin: Portuguese absoluto, Catalan absolut, French absolu, Italian assoluto; Eastern Vulgar Latin: Romanian absolut
absolver (Verb) "to absolve"

13th cent. Borrowed from Latin absolver "to absolve" but also "to loosen." From ab- "away" and solvere "to loosen." See solver.

Romance: Western Vulgar Latin: Asturian (Junquera Huergo) asuelver, Asturian (Parres) absolver, Portuguese absolver, Catalan absoldre, French absoudre, Italian assolvere; Eastern Vulgar Latin: Romanian absolvi
abuelo (Noun) "grandparent"

11th cent. Old Spanish abolo. First attestation of abuela is 13th cent. From Vulgar Latin *aviolus, from Latin avus "grandfather" (see ayo and aya) and diminutive suffix -olus (see -uelo).

Romance: Western Vulgar Latin: Asturian güelu, French aïeul

Latin avus, without the diminutive suffix -olus, became Spanish ayo "tutor."
acá (Adverb) "here," "hither"

11th cent. From Vulgar Latin *ac(cu) hac from Latin eccum hac "look (at) this." For a continued etymology of eccum, see aquí. Latin hac "in this manner" is from Proto-Italic *χā-ke "by means of this here." From Proto-Indo-European *geh2- or *ǵheh2-, both meaning "this" with suffix *-ḱe "here."

Its use as a contrastive with aquí is mostly in Latin America and is much less frequent in Iberia. Acá is used with motion verbs (e.g., vienes acá "you come here") and aquí is used elsewhere (e.g., se renta carros aquí "cars are rented out here").

Romance: Western Vulgar Latin: Asturian acá, Portuguese , Italian qua

Acá's history is one of perpetual reinforcement as the word loses strength in meaning over time. PIE *h1e- + *-ḱe > PIt. *ek(e) > PIt. *ek(e) + *-ke > PIt.*ekke > Latin ecce > Latin eccum hac > Spanish acá.

Mas acá, meaning "this side" or "this way," derives from its use as an intensifier. Unlike mas allá, which neatly translates as "beyond," mas acá has no isomorphic equivalent.
Aca, Acahua (Surname)

From Nahuatl acatl "cane," "reed."

Variant Acahua "owner of canes" is from acatl and hua, to indicate a possessive agent.
acabado m. (Adjective, Noun) "finished;" "finish"

13th cent. Past participle of acabar.
acabar (Verb) "to finish," "to end"

12th cent. Literally "to bring something to a head (i.e. 'conclusion')." From a- and cabo.

Romance: Western Vulgar Latin: Asturian acabar, Portuguese acabar, Catalan acabar, Occitan acabar
acaso m. (Adverb, Noun) "maybe;" "chance"

15th cent. From a- and caso.

Romance: Western Vulgar Latin: Asturian acasu, Portuguese acaso
acceder (Verb) "to accede"

18th cent. borrowing from Latin accedere "to approach." From ad- "toward" (see a(d)-) and cedere "to move," but more commonly "to yield" (see ceder).
acceso m. (Noun) "access"

15th cent. Borrowed from Latin accessus 'id.' From accedere "to advance upon" (see acceder).