Our kid
In Manchester and across the north of England, "our kid" means my brother or sister, usually a younger one, and is also used warmly for a close friend. The "kid" has nothing to do with age: a sixty-year-old can be someone's our kid.
In practice
"Our kid's coming down this weekend" means a sibling is visiting. Used in the third person - "his our kid" - it still means a brother or sister. Addressed directly to a friend, it becomes a term of affection, a little like "mate". The phrase became famous well beyond the north through the Gallagher brothers of Oasis, who have used it about each other in interviews for decades.
Why it matters to newcomers
It is one of the first northern phrases that confuses people from elsewhere, who assume the speaker is talking about a child. In Manchester it marks warmth and family, and it is fine for a newcomer to understand it long before using it.
Related
- Mither - what our kid does when they want something
- Mancunian - who says it
- Barm - another word that marks you as local
Source: Wiktionary: our kid.