The compound "tax-favored" is a modern financial and legal term constructed from two well-established English words. "Tax" originates from the Latin taxare, meaning to assess or charge, which entered English through Anglo-Norman. "Favored" derives from the Latin favor, implying kindness or partial support. When combined, the term literally means "tax-assessed in a preferential manner." This construction logically evolved in the 20th century within legislative and financial discourse to describe investments, accounts, or income streams that are intentionally designed or officially designated to receive beneficial treatment under a government's tax code, thus encouraging specific economic behaviors.

Structure: tax (tax) + favored (preferred) - tax: From Latin taxare ("to appraise, charge, censure"), via Old French. In this compound, it functions as a noun modifier meaning "related to taxation." - favored: From Old French favor, from Latin favor ("goodwill, partiality"), combined with the past participle suffix -ed. In this compound, it functions as an adjective meaning "preferred" or "granted an advantage."