Earlier quoted context omitted.
You're making this weird semantic distinction that is irrelevant. Nobody is arguing that Spain was a single, completely unified polity before the Islamic conquests. But it was controlled by the Christian Visigothic Kingdom of Spain, and then it was conquered by the Islamic Umayyads, so the reconquista was to bring it back under Christian rule.
The semantic distinction is relevant because Reconquista, with the capital R and everything, is an ideological, propagandistic narrative by the Spanish (central government) originating in the 20th century.
> the first time that the term "reconquista" was used to refer to the fight against the Muslims was in the work of José Ortíz y Sanz entitled Compendio cronológico de la historia de España, published after 1795. The use of the term, however, did not spread until the 1840s thanks to two new editions of Ortiz's work and the publication of the Historia general by Modesto Lafuente.
So the term did not originate in the 20th century, but it was added to the dictionary in 1936.
16th-19th century historians would have used the term "restoration". The northern kingdoms prosecuting this supposed restoration were keen to claim their legitimacy as a continuation of the entire Visigoth Kingdom, and made it their business to recapture it... even if they never held that territory.