Origins
The word enable is a straightforward English construction — en- plus able — but its roots reach back to one of Latin's most productive verbs. The adjective able entered English from Old French hable, from Latin habilis meaning 'easily handled' or 'apt', from habēre — 'to hold, to have'.
Habēre is among the most fertile roots in the Romance languages. From it English inherited ability, habit, inhabit, exhibit, prohibit, and rehabilitation. The connecting thread is possession or control: to be able is to hold the capacity; a habit holds you in a pattern; to inhabit is to hold a place.
French Influence
The en- prefix, from Old French (ultimately Latin in-), turns adjectives into verbs: enlarge, enrich, enable. To enable someone is to put them in a state of being able — to hand them capability they lacked.
In the 20th century, electronics gave enable a precise technical meaning: to activate a circuit or feature. Computing adopted this wholesale. An enabled setting is one switched on. This technical sense preserves the etymology neatly — to enable is still to make something capable of functioning.