a high-level estimate intended to be a reasonable approximation upon which decisions or further work can be based, drawing on the notion that a grenade need only be in the vicinity of its intended target to be effective, given its blast radius; this jargon has playful, martial undertones and is likely to be heard when rapidly grasping the quantitative contours of the situation is more important than precision; similar to t-shirt sizing, a similar concept used for rough categorization; the folk saying “close only counts in horseshoes and hand grenades” has the opposite sense, and is said when an exact target must be reached for an achievement to be meaningful; see also crayon analysis