pillar [ME] The Latin word pila ‘pillar, pier’ is the source of pillar and also *pile. People were shunted from post to pillar, ‘from one place to another’, back in the early 15th century, but for some reason the version from pillar to post came into use in the middle of the following century and soon became the favoured choice. Its origins lie in the sport of real tennis, played in an enclosed court (a bit like the one used for squash, only much larger) with sectioned walls and buttresses off which the ball can rebound. These are the ‘posts’ and ‘pillars’ of the expression. The game developed from one played by 11th-century monks in the cloisters of monasteries.