Sewing question (cut a yoke?)

I know that some of you wise ladies will know the answer to this…I have
been searching high and low for nightgowns for my little girl, and they are
sooo hard to find! Walmart & Target don’t carry them in her size (2T) and
the stores that do carry them sell them for about $15.
So, someone gave me 11 yards of fabric that would be perfect for
nightgowns. My grandma told me to “cut a yoke and gather some
material”….what does that mean????

With 11 yards, I can play with it and try to figure it out but if anyone
can elaborate on those instructions, I would appreciate it!!

Thanks!
Valerie – mom to 2 boys and its just too cute to have a little girl in
night gowns 😛