Vital point
A Vital Point is an important shape point for both players. Vital points are usually urgent. (Though not all urgent moves are concerned with shape) Vital points are key points in either the local, or, perhaps less commonly, the global context[1].
Example 1
White is a classic example of a vital point
This Hikaru no Go fan site offers the following explanation (loosely rendered).
A point that maximizes the effectiveness of the stones. Similar to tesuji or best move, but with a different nuance. A tesuji is a strong move within the context of a sequence of moves, but if you occupy a vital point, it's hard for the opponent to gain a good result no matter where he plays. Of course, the two are not completely distinct.
Example 2
is a vital point for shape.
From Jowa, Powerful Fighter (Gohwan Jowa) by Takagi Shoichi, p. 60.
Example 3
Below are examples from TournamentGo1992, page 152 (left column) and page 154 (right column). They are taken from the game record and commentary from the game Otake Hideo (White) vs Kobayashi Koichi (Black), 30 September and 1 October 1992, the third game of the 17th Meijin Title. [1]
Takemiya is quoted as saying "White should play...at in Dia. 3. After , he can take up position with . I think that the latter is the vital point of the whole board."
Takemiya is quoted as saying "Black 61 (). As mentioned above, this is the vital point, the key point of the whole board." Here is using the term in the sense of Tennouzan.
More examples
Vital point in life and death
Vital point can refer to the key point in the context of a life and death problem. This has been traditionally called a nakade, while "vital point" is aiming to translate the Japanese term "kyuusho".
For example, the proper killing technique in this position is to hane at first, then hit the "vital point" or nakade of .
Likewise, is the proper way to live with maximum number of points, but we wouldn't usually refer to it as the "vital point".