Wiktionary
n. (context biology English) The normal physical exit area for undigested solid food in living beings.
Wikipedia
The anal pore is where waste leaves a microscopic organism after the nutrients from the food has been absorbed into the cytoplasm. Some of these single-celled organisms have multiple anal pores to help deal with their larger food needs. The waste is ejected by the food vacuole that has nothing but waste products remaining bursting and the waste products proceed to flow out. It is essentially a miniature version of the anus found in more complex organisms.
Usage examples of "anal pore".
It slid sudsing along on a tongue of slime, engulfing its slow, savoring way down its row, leaving behind black stumps where movement and struggle had been, and every so often, emitting from its anal pore a flatulent spew of fresh, bright gems.