The only free and comprehensive online etymological dictionary of the Spanish language
tanga (2) f. (Noun) (underwear) "thong"
From Kimbundu ntanga "loincloth."
tángana, tangana f. (Noun) "wooden stake used in quoits," "quoits;" "cheater;" (Antilles & Venezuela) "violent discussion"
18th cent. From tanga (1).
tangar (Verb) (slang) "to cheat"
From tanga (1) (cf. the secondary meaning of tángana meaning "cheat").
tango (1) m. (Noun) "quoits"
19th cent. Name of a game played by players tossing discs at wooden stakes in the ground. A traditional game played throughout all of Spain; the earliest recorded name is "chita." From the Old Spanish phrase yo tango "I touched it." In Old Spanish times, when a disc successfully strikes the wooden stake, the player announces "yo tango."
tango (2) m. (Noun) "tango"
19th cent. Of uknown origin. Perhaps from a Niger-Congo language.
tantear (Verb) "to estimate"
Late 15th cent. Probably verb formed from tanto, though the semantics are hazy.
tanteo m. (Noun) "trial;" "estimate"
16th cent. From tantear.
tantico (Adverb) "little"
From tanto with diminutive suffix -ico.
tanto (Adjective) "so much"
12th cent. From Latin tantum, accusative of tantus 'id.' From Proto-Italic *tānto- "so great." From Proto-Indo-European *teh2-nt-(o-) 'id.,' from demonstrative stem *teh2- (see tal) and *-nt(o)- (a common ending of unclear meaning, see Lowe (2011) for discussion).
Tan (adv.) "so," "also" is an apocopated form.
Indo-European
Romance
Portuguese tanto, Catalan tant, French tant, Italian tanto
Italic
Oscan etanto "so great," Umbrian etantu 'id.'
tara (1) f. (Noun) "tare"
Verly early 16th cent. 15th cent. Old Spanish atara. From Andalusian Arabic ṭáraḥ 'id.,' from Arabic ṭarḥ