post [OE] English has three words spelled post. The one meaning ‘a long, sturdy piece of wood’, and ‘to display a notice in a public place’ (from fastening it to a post) is from Latin postis ‘doorpost’. The other two, ‘the official service or system that delivers letters and parcels’, and ‘a position of paid employment’, are both from Latin ponere ‘to place’. The ‘delivering letters’ sense arose from its application to each of a series of mounted couriers who were stationed at suitable places along a route and carried important letters and despatches on to the next post post-haste [M16th]. A fourth post is found in terms like *posthumous, post mortem, and post-war. This comes from Latin post ‘after’. In American English to go postal is to become irrational and violent, especially as a result of stress. This dates from the 1990s, and arose as a result of several cases involving employees of the US postal service running amok and shooting down their colleagues. The phrase can also be used to mean ‘to get very angry, to fly into a rage’. See also mail, positive.