The Spanish verb 'blindar' (meaning 'to armor' or 'to shield') comes from the French word 'blinder' with the same meaning. The French term itself originated from the German word 'blenden', which meant 'to blind'. When the word entered Spanish, it adopted the standard -ar verb ending common to Spanish infinitives.

The semantic evolution from 'to blind' to 'to armor' is quite logical - the idea of blocking visibility (blinding) extended to the concept of blocking or protecting against attacks in general. Just as blinding prevents visual access, armor prevents physical access or damage.

While 'blindar' itself is a relatively common Spanish word, it has given rise to related terms like 'blindaje' (armor, armoring) and 'blindado' (armored). These words form a family of terms all related to protection and armoring in Spanish.

While not directly related, English speakers might find it interesting that the English word 'blind' shares the same Germanic root as 'blindar', though their meanings have diverged significantly. The English 'blind' retained the original sense of lacking sight, while the Spanish term developed the specialized meaning of protection or armoring. Another related English word is 'blinder', as in the equipment used on horses to limit their field of vision, which shows a meaning somewhere between the original 'blocking vision' sense and the modern Spanish meaning of 'protecting/armoring'.