Some terms related to Sudoku:
grid: the most common Sudoku is a square composed by 9x9 cells.
box, block, zone, subgrid: each one of the nine 3x3 grids that compose the whole square.
stack: three vertical connected blocks.
band: three horizontal connected blocks.
chute: either a band or a stack.
given, clue: the initial defined values.
proper puzzle: Sudoku with a unique solution.
irreducible puzzle: is a proper puzzle where no givens can be removed leaving it a proper puzzle.