The word taxation was borrowed in 1325 from Anglo-Norman taxacioun, which comes from Old French taxacion, which comes from the Latin accusative taxionem, which could mean "appraisal" or "rating", because tax collectors need to ascertain the value of things before they collected the government's share. The root there is the verb taxere, which could mean "evaluate" but also had connotations of handling money, and could mean "charge". Because of that connection to tangible currency, it's thought that taxere derives from tangere, which meant "to touch". That, through Proto-Italic tango, would eventually come from the Proto-Indo-European reconstruction tag, meaning "touch" or "handle". Although usage of the word taxation has been decreasing since the early twentieth century, the frequency of the word tax has skyrocketed since then.
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.