What is the linguistic and technical definition of "waqiʿat ʿayn" (specific incident), what are the similarities and differences between it and the Shariah concession (rukhsah), and what are the incidents and prophetic traditions that fall under it, such as the incident of the suckling of the adult?

The phrase "waqi'at 'ayn" (a specific incident) means an issue that occurred to a particular individual, and it resembles a special dispensation for them, such as the Prophet Muhammad's (peace be upon him) permission for Abu Burdah to sacrifice a young goat. This differs from a general dispensation, like wiping over the leather socks (khuffayn), where the consideration is the generality of the wording, not the specificity of the reason.