"Birthdate" is typically considered as one word.
The conventional form is "birth date" as opposed to birthday (one word).*Oddly, although the one-word form birthdate is not widely accepted (Wiktionary being an exception), some spell-checkers do accept the plural birthdates.
If its for a crossword puzzle, try BirthDate- as one word
It is used as one word.
no it is not an one word it is of two word
I think the word "ongoing" is only one word, but it has two syllables that are two separate words.
Hipbone is one word.
The word "hairbrush" is typically written as one word, not two.
One word, two syllables
It is one word.
one word
It is one word.
"Hardworking" is one word.