Feces (also known as poop, droppings, or manure) is the product expelled from a being's digestive tract, consisting of bodily wastes.
In advanced civilizations, bodily waste was deposited in a toilet sent to the waste extraction system, where after various processes, would be recycled through biomatter resequencing. For infants, feces was often collected in a diaper.
When Miss Malvin's fourth grade class from Worley Elementary School in County Kerry, Ireland sent letters to Enterprise NX-01 in 2151, Molly McCook wanted to know "When you flush the toilet, where does it go?". After Captain Archer passed the question to Commander Tucker, he responded with: "A poop question, sir?!" (ENT: "Breaking the Ice")
Doctor Phlox found that Altarian marsupial droppings contained the greatest concentration of regenerative enzymes found anywhere. Archer found the idea of using droppings for regenerative purposes disgusting, however, Phlox reminded him that if he was going to try to embrace new worlds he must also try to embrace new ideas. (ENT: "Broken Bow")
Bodily waste collected and used for agricultural purposes in the form of fertilizer, typically called manure, consists of high levels of methane. Kathryn Janeway recognized this upon detecting methane on a truck found in 2371. (VOY: "The 37's")
Some use the term "manure" as a metaphor for purposes of making a derogatory comment. The Species 8472 recreation of Boothby once referred to the Federation's concepts of "tolerance for all species" and the Prime Directive as "Targ manure." (VOY: "In the Flesh") Similarly, the slang terms "shit" and "bullshit" were colorful metaphors which referred to the manure in general and that produced by a bull, respectively. The cursing "Merde" (meaning "shit") was also used in French language. (TNG: "The Last Outpost", Star Trek Generations; Star Trek: First Contact; Star Trek)
In addition to metaphoric usages, the idiomatic usage of the term "poop", as in "party pooper", refers to someone that is a killjoy. In 2372, the little woman referred to the Clown as a poop because he started feeling sorry for himself. (VOY: "The Thaw") While investigating a proto-nebula in 2375, The Doctor made an offhand comment about the Borg being the "party poopers of the galaxy", after Seven of Nine discouraged his attempt to use his holo-imaging device, and subsequently offered to begin a new social exercise with Seven to develop her joie de vivre. (VOY: "Drone")