The News & Views WotY for 2009 is 'critical'. But this is not an accolade. This devilish little word has an honourable place in the scientific lexicon when bound together with such terms as 'mass', 'angle' and 'temperature'. But in an evolutionary battle to convey the sense of 'having a decisive importance', it has all but killed off such alternatives as 'crucial', 'vital', 'essential' and 'necessary'. We can but hope that its spread is halted in 2010.