If you are talking about Freytag's pyramid, the "climax" is always Act 3. In terms of dramatic tension, this reaches its peak when Othello is about to kill Desdemona.
For some people the word "climax" has a technical sense when discussing a play. This might cause them to identify the climax with act 3 of any Shakespearean play. In a non-technical sense, the climax of the play comes when Othello smothers Desdemona. He had a chance up to that point but none after.
Othello
Milan
the climax is that cloud-dancer dies
There is no novel of Othello, actually. The famous Othello is a play by Shakespeare. Plays are not novels. If Othello was white, Othello wouldn't have been insecure, his relationship with Desdemona wouldn't be disapproved of and Iago might have hated Othello less. That is, of course assuming that Othello is white and so is everybody else. If Othello were white and everyone else was black, the story would be much the same because Othello's insecurity stems from his feeling of otherness, his feeling that he was different from everyone else. Othello has in fact been staged in this way, with a black cast and a white Othello. It has also been staged with actors playing Othello who are not black but are different from the rest in some other way.
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They both have scenes, climax, and a resolution.
it is similar to the climax of the story
she got raped
I don't think there is any real climax in the novel, but their is definitely an anticlimax at the end of the novel. Throughout the novel clues are unfolded into how the story could end (Lennie's death/ death of Candy's dog/ death of mouse).
The climax was when he asked the big question. "I want you to locate the climax of the novel," Said the teacher. The climax is the biggest, most influential point in a story.