Little Nanny Etticoat

Origin

It is not certain when this rhyme first appeared, but by the 19^th century, it was already included in most nursery rhyme collections.

There must have been countless nannies who recited this verse to the children under their care, wanting to see how clever the kid was because it’s not just a rhyme but a riddle to which the toddler was expected to come up with an answer. By the way, a petticoat was an undergarment typically worn under a dress.

The version with an added line in the middle might make the guessing a little easier:

Little Nancy Etticoat
With a white petticoat,
And a red nose;
She has no feet or hands,
The longer she stands,
The shorter she grows.

While it might be hard to find the correct answer nowadays, in those times back then, it was right under the nose of the children when in the evening no daylight came through the windows anymore.
The white petticoat is melted wax, the red nose is a flame at the top and answer to the riddle that all smart kids knew was the candle.