Wiktionary
n. (alternative form of close-stool English)
Wikipedia
A close stool was an early type of portable toilet, made in the shape of a cabinet or box at sitting height with an opening in the top. The external structure contained a pewter or earthenware chamberpot to receive the user's excrement and urine when he or she sat on it; this was normally covered (closed) by a folding lid. "Stool" has two relevant meanings: as a type of seat and as human feces. Close stools were used from the Middle Ages (the Oxford English Dictionary gives the first citation as 1410) until the introduction of the indoor flush toilet.
Usage examples of "close stool".
These papers are delivered to a set of artists, very dexterous in finding out the mysterious meanings of words, syllables, and letters: for instance, they can discover a close stool, to signify a privy council.