Ibility

Part of speech: noun

Definitions

1. A suffix attached to adjectives ending in -ible to form nouns naming the quality or capability of being something, as in visibility or flexibility
2. A word ending used to turn an adjective into a noun that expresses a capacity, state, or condition of being able to be acted upon
3. A noun-forming suffix that indicates the quality or state of being capable of a certain action or treatment, as in possibility

Etymology: The word here is the suffix "-ibility," which English builds by attaching "-ity" to adjectives ending in "-ible" (so "visible" becomes "visibility"). It is not a standalone word, and its history is really the history of the two pieces joined together. The "-ible" part comes from Latin "-ibilis," a suffix meaning "able to be" or "capable of being," as in "credibilis" (believable) and "visibilis" (visible). The "-itas" ending, which gives English "-ity," is a Latin noun-forming suffix that turns adjectives into abstract nouns naming a quality. When the two were combined in Latin as "-ibilitas," they produced abstract nouns for capacity or quality. English took these over in large numbers from Latin and Old French during the late Middle Ages and the Renaissance, often through French forms such as "-ibilité." Because "-ity" became so productive, English speakers could create new "-ibility" nouns from any "-ible" adjective, which is why the suffix now appears in so many modern coinages.