A shape that is curved and without sharp angles(noun)
WordNet. Princeton University. 2010.
Use "round shape" in a sentence
"The headdress was, as far as I can remember, also of white silk, twisted into a round shape and padded, like a turban, yet resembling our priests 'birettas to a certain extent, for at the top it had ridges like theirs and also a tuft of silk."