crystal lattice is the orderly array of points in space. i.e. a lattice is a structure of crystals where each lattice point represent an identical group of atoms.
a unit cell is a crystal structure that 's the smallest group of atoms possesing the symmetry of the crystal. i.e. it is the fundamnetal unit of crystal lattice
assume if crystal lattice is a wall then d bricks r d unit cells
unit cells follow a pattern ....... n dat pattern is repeated to form a crystal lattice
hope that it helped u :)