Pentomic (cf. Greek pent(e)- +-tome "of five parts") was a structure for infantry and airborne divisions adopted by the US Army between 1957 and 1963, in response to the potential use of tactical nuclear weapons, on future battlefields. It was intended that the five subordinate units, which were often referred to as battle groups (to distinguish them from traditional units), would be able to deploy and engage in operations more rapidly than conventional brigades, whilst also having greater offensive capabilities than conventional battalions.