What is the meaning of roundness?

noun

• The fullness of a tone of voice.
  • usage: "there is a musky roundness to his wordiness"
  • synonyms: rotundity
• The quality of being round numbers.
  • usage: "he gave us the results in round numbers, but their roundness didn't affect the point he was making"
• The property possessed by a line or surface that is curved and not angular.
• The bodily property of being well rounded.
  • synonyms: plumpness, embonpoint