Naked Pair
a Naked Pair is when 2 digits are the only candidates in 2 cells within one house. Since one of the cells must contain one of the candidates, and the other cell must contain the remaining candidate both candidates can be removed from the remaining cells in the house.
In this example, the naked pair 1/7 in row 6 have been highlighted.
Since 1 and 7 must be in the highlighted cells, all the remaining candidates (highlighted with red) in the row can be eliminated.
Naked Triple
A Naked Triple is similar to a Naked Pair, but consists of 3 digits spread over 3 cells. Each cell does not need to contain all candidates, but can contain any combination of the 3 candidates.
For example in this puzzle, the naked triple in row 9 is marked and consists of the tuples 1/7, 1/2/7, and 1/2/7.
Other valid combinations with these 3 digits could also be 1/7, 1/2, and 2/7, or 1/7, 1/2, and 1/2/7.
The digits 1,2, and 7 must be in the highlighted cells, so they can be eliminated from the remaining candidates in the row.
Naked Quad
The final naked subset is the Naked Quad, which is the same as the others, but with 4 digits spread over 4 cells. As with the Naked Triple, not all cells have to contain all digits, but they can’t contain any candidates other than those 4 digits.
Every naked subset is also always complemented by a hidden subset.