diffuse; defuse, vb. To “diffuse” something is to disperse it from a single source. To “defuse” is to make something threatening safe, especially a dangerous situation or a bomb (by deactivating it). “Diffuse” can have very different connotations, depending on its context, because of how dispersal can work. When dye is dropped into water, as it diffuses it both increases (in apparent size) and decreases (in concentration). Similarly, light that is diffused, as through a window shade, is made softer. But when the thing being diffused is not diminished by being spread — literacy or religion, for example — it grows in both size and strength. So we find a connotation of building rather than weakening in the Carnegie Foundation’s mission of promoting “the advancement and diffusion of knowledge and understanding.” The notion that something diffused is softened like filtered light may explain why some writers misuse “diffuse” for the similar-sounding “defuse” — e.g.: o “Leaders were hopeful last week that the agreement would diffuse [read ‘defuse’] the possibility of violence at today’s march.” Joe Hallett, “Cincinnati: Has Anything Changed?” Columbus Dispatch, 7 Apr. 2002, at A1. o “With almost 1 million troops stationed on both sides of the India-Pakistan border and with Pakistan having recently test-fired another round of missiles, Deputy Secretary of State Richard Armitage and Defense Secretary Donald Rumsfeld were sent to the region for emergency exercises in diplomacy to try to diffuse [read ‘defuse’] tensions.” “The India-Pakistan War Machine,” Wash. Times, 5 June 2002, at A16. For more information about the Language-Change Index click here. Quotation of the Day: “A cliché; begins as heartfelt, and then its heart sinks. . . . The trouble with a cliché; like “take it to heart” is that by now it’s almost impossible to take it to heart.” Christopher Ricks, “Clichés,” in The Force of Poetry 356, 356 (1984).