Akademik

A regular arrangement of units into an array such that a plane passing through two units of a particular type or in a particular interrelationship will pass through an indefinite number of such units; e.g., the atom arrangement in a crystal.

lat·tice 'lat-əs n a regular geometrical arrangement of points or objects over an area or in space: as

a) the geometrical arrangement of atoms in a crystal called also space lattice

b) a geometrical arrangement of fissionable material in a nuclear reactor