means The long, coiled tube of the digestive tract running from the stomach to the anus, where food is broken down further and nutrients and water are absorbed.

from From Latin 'intestinus,' meaning 'internal' or 'inward,' built on 'intus,' meaning 'within.' The same root gives us 'intestate' (a cousin in form only — dying without a will), but the gut-sense came through the Latin plural 'intestina,' the 'inner parts,' which is exactly what they are: the works on the inside.