poison [ME] A poison does not necessarily need to be in liquid form, but in early use the word meant a drink or medicine, specifically a potion with a harmful or dangerous ingredient. The source was Old French poison ‘magic potion’, from Latin potio, also the source of potion [ME]. The saying one man’s meat is another man’s poison has been around for centuries and was being described as long ago as 1604 as ‘that old moth-eaten proverb’. A similar idea is found in the work of the Roman poet and philosopher Lucretius (c.94–55 bc): ‘What is food to one person may be bitter poison to others.’ A chalice [ME] from Latin calix, ‘cup’, also the source of the botanical calix [L17th]) is a large cup or goblet, and a poisoned chalice something that seems attractive but likely to be a source of problems. A poisoned chalice features in Shakespeare’s Macbeth, and is the source of our expression.