organic chemistry - When a bond is formed between an electophile and a nucleophile, they both lose energy and become more stable right?

This is a section from clayden's organic chemistry textbook. I do not understand why it says energy gain and not energy loss

Answer

In the context of the picture provided, it seems just a matter of language choice. When energy is lost, it is gained somewhere else because of conservation of energy. So a change in energy corresponding to a gain is at the same time a loss elsewhere. The author of that diagram could have used interchangeably energy loss without loss of meaning.