The word 'toxic' has become ubiquitous. The financial crisis has introduced us to 'toxic loans', 'toxic debts' and 'toxic assets', while politics is awash with 'toxic briefings', 'toxic language' and 'toxic' personalities. And you might find yourself in a 'toxic relationship' or married to a 'toxic wife'. These new toxins have swamped old-fashioned worries that, say, your firm's products might contain 'toxic chemicals' or cause 'toxic reactions'. Things used to be 'toxic' if they killed you, rather than just ruining your week or your business. It has meant poisonous since the 17th century, becoming a medical term in Victorian times for diseases resulting from poisoning: the best-known example, 'toxic shock syndrome', was named only in 1978. The word's source is the Greek toxikon pharmakon, 'poison for smearing on arrows'. Toxikon was the part that meant arrows, but in the Roman adoption of the phrase, toxicum meant poison. We inherited both, which explains why 'toxicology' is the study of poisons, while 'toxology' is archery. A useful pub-quiz fact, if you're not too intoxicated to remember it.