Locked Candidates

Type 1 (pointing): if all candidates for a digit inside a box lie in one row (or column), then that digit must go in that row inside the box. So it can be removed from the rest of that row outside the box.

Type 2 (claiming): if all candidates for a digit inside a row (or column) lie within one box, the digit must go in that box in that row, so it can be removed from the other cells of the box.

Both types are the same fact seen from two sides: the digit is "locked" into the cells where a box and a line meet.

Notation

Locked Candidates Type 1 (Pointing): 5 can be removed from r2c7.