1. The pool of afterbirth, amniotic fluid and placenta that originates after a beached whale has given birth on land.
2. The area immediately adjacent to an incredibly fat woman who is in the throes of labour. Anyone standing in the birthbay is likely to be sprayed with awful things.
3. When your friend wishes you a happy birthday but unfortunately spells 'birthday' wrong.
(Defined word capitalised for emphasis)
1. After the government managed to get the beached whale and its newborn baby back into the water, they ran out of funds, and were forced to turn the BIRTHBAY into a paddling pool for the children.
Henry: What happened to you, Daniel?
Daniel: I was helping this obese friend of mine give birth, and I got sprayed with all of this afterbirth!!
Henry: Well, you shouldn't have been standing in the BIRTHBAY!
Daniel: It's my birthday today.
Henry: Happy BIRTHBAY, Daniel!
Daniel: BIRTHBAY... don't you mean birthday?
Henry: Yes... but happy BIRTHBAY anyway!