Callipygian is a rather interesting word with a fascinating etymology. An obscure term meaning "pertaining to beautiful buttocks", usage has actually been rising slowly since its introduction in 1800 from the Greek word kallipygos. Funnily enough, this was named after a statue! The Kallipygos was a sculpture of the goddess Aphrodite in the city of Syracuse (this was lost to the ages, although the Venus Callipyge in Naples was a Roman knockoff which purportedly looks very similar), famed for its perfect posterior. That was the first attestation of the word in Ancient Greek, but its component terms were around for much longer: kallos meant "beauty" and pyge meant "buttocks". Kallos, which also yielded the name of the goddess Callisto, comes from kalos, a word meaning "good" and deriving from Proto-Indo-European kal, also along the lines of "good" or "beautiful". Pyge, meanwhile, also traces to Proto-Indo-European, in this case to the root pouga, with about the same definition.
Adam Aleksic, a rising sophomore studying linguistics and government at Harvard University, has been described as the internet's sixth most famous etymologist. He also has disturbing interests in politics, vexillology, geography, board games, conlanging, and law.