The only free and comprehensive online etymological dictionary of the Spanish language
tara (2) f. (Noun) (Venezuela) "tally stick"
Traditionally supposed to be a variant of tarja (2) from Old Spanish taja, but the sound changes are unexplained.
In 1694, the Canarian historian Tomás Arias Marín de Cubas noted that indigenous Canarians called astrological etchings found in caves tara and tarja. It may be that the sound change from tarja to tara arose from the early Canarian peoples, or it may be that the etchings are named after the Guanche toponym Tara and that there is no connection between the Canary islands and this word.
tara (3) f. (Noun) (Bolivia & Peru) "Tara spinosa"
19th cent. The name of a small, thorny bush cultivated as a source of tannins. From Quechua tara 'id.'
tarde (Adverb, Noun) "late;" "afternoon"
12th cent. From Latin tarde 'id.,' from tardus "slow." Of unknown etymology.
Portuguese tardo, Catalan tard, French tardif, Italian tardo, Aromanian tãrdzãu, Romanian târziu, Sardinian taldu
tarea f. (Noun) work; "homework"
Very late 15th cent. Old Spanish atarea. From Arabic ṭarīḥa "endeavor," from Classical Arabic ṭáraḥa "to throw."
Portuguese tarefa, Galician tarefa
When borrowing nouns from Arabic, Spanish tended to preserve the article al- before the noun and interpret it as part of the noun. For example, Alhambra is from Arabic al-Hamra. Interestingly enough, tarea does not preserve al-. "A number of Arabisms that have entered Spanish show no traces of the agglutinated article: bellota 'acorn', berenjena (but sporadic and later alberengena ...) 'eggplant', jarro/jarra 'jar', rehén (alongside OSp. arrehén) 'hostage', tambor (originally atamor) 'drum', tarea (OSp. atarea) 'task', taza 'cup'." ~ S. Dworkin, A History of the Spanish Lexicon (2012)
tarja (1) f. (Noun) "shield"
15th cent. Borrowed from Old French targe 'id.' Borrowed from Old English *targe 'id.' or a similar Germanic source. From Proto-Germanic *targōn- "edge." Derived from a pre-form *dorgh- "to separate" of unknown origin.
Portuguese tarja, French targe, Italian targa
Old Norse targa "small shield," Old High German zarga "edge," Old English targe "small shield"
Old Church Slavonic po-dragъ "edge"
tarja (2) f. (Noun) "tally;" "tallying stick"
Very Early 17th cent. Old Spanish taja, although the appearance of -r- in Modern Spanish is unexpected (compare tajar, which has remained unaltered). From Latin taliare "to tally" (see tajar).
Asturian tallar, Portuguese talhar, Catalan tallar, French tailler, Italian tagliare, Aromanian talj, Romanian tăia
tarjeta f. (Noun) "card"
19th cent. Borrowed from Old French targette "small shield," diminutive of targe "shield" (see tarja).
Italian targhetta
tarugo m. (Noun) "wooden plug," (El Salvador & Nicaragua) "wood block;" (slang) "stupid person"
14th cent. Of unknown origin but probably from a pre-Roman language as *tar-u- "wooden stake" (cf. tarusa).
Portuguese tarugo, French taranche, French (Rouergue) tarenco
Gaulish tarinca "stake," Old Irish tairnge 'id.'
tarusa f. (Noun) (Asturian, Leon, Palencia, and Zamora) "quoits"
A traditional game played by throwing discs at wooden stakes. Origin unknown but possibly from a pre-Roman language *-tar-u- meaning "wooden stake" (cf. tarugo, which is suspected to be from Iberian, and possibly tara (2) - although evidence suggests that, as a word, tara developed in the Canary Islands).
Asturian tarusa
taxi m. (Noun) "taxi"
Shortened from taxímetro. See also taxi-.