What is an 'Ablative Absolute' and how can I translate it from Latin to English?

An ablative absolute is a construct very common in Latin. It comes from the verb "absolvo" (to free) and it literally means "a freed ablative" in the sense that it is completely independent of every other part of the period. It is formed by a participle (either present or past) and a noun, both of them are in ablative and share the same quantity and gender.