ringlet vs round shape

ringlet and round shape both are nouns.

Word	Noun	Adjective	Verb	Adverb
ringlet	Yes	No	No	No
round shape	Yes	No	No	No

As nouns, round shape is a hypernym of ringlet; that is, round shape is a word with a broader meaning than ringlet:

ringlet: a round shape formed by a series of concentric circles (as formed by leaves or flower petals)
round shape: a shape that is curved and without sharp angles

ringlet (noun)	round shape (noun)
any of various butterflies belonging to the family Satyridae	a shape that is curved and without sharp angles
a little ring
lock of hair in the shape of a spiral or curl
a round shape formed by a series of concentric circles (as formed by leaves or flower petals)