What is "nannies"

Nanny \Nan"ny\, Nannie \Nan"nie\(n[a^]n"n[y^]), n.; pl. nannies.

1. a caretaker for a child; a child's nurse; a nursemaid.

2. Grandmother; -- a child's word, used especially as a form of address. See also nana.

n. (nanny English)

"Nannies" is the third episode of the eighth season of the CBS sitcom How I Met Your Mother, and the 163rd episode overall.