The compound 'toll-free' is a modern creation from the mid-20th century, directly combining two native English words. 'Toll' has ancient Germanic roots referring to a tax or charge, historically levied for passage or services. 'Free' is an equally ancient concept in Germanic languages, denoting liberty and absence of obligation. The logic of the compound is transparently literal: a service that is 'free of toll' or charge. It was specifically coined in the context of telephony to describe a call where the cost is borne by the recipient, not the caller, thus removing a financial barrier to communication.

Structure: toll (charge) + free (without) - toll: From Middle English 'tol', 'toll', from Old English 'toll', 'tol', from Proto-Germanic tullaz (a charge, fee). Functional role: Noun root denoting a payment or charge. - free: From Middle English 'free', from Old English 'frēo', from Proto-Germanic frijaz (not in bondage, beloved). Functional role: Adjective meaning without cost or restriction.