fecal

The word 'fecal' is a direct descendant of the Latin term faeces, the plural of faex, which originally referred to the dregs or sediment at the bottom of a wine vessel or other liquid. This literal sense of worthless residue was extended metaphorically in medical Latin to denote bodily waste. The adjective-forming suffix '-al' was attached in English to create a term specifically describing anything pertaining to this waste matter. Thus, the modern clinical term retains the ancient logic of defining something by its status as the discarded, sediment-like byproduct of a biological process.