What is the meaning of rhetoric?

noun

• Using language effectively to please or persuade.
• High-flown style; excessive use of verbal ornamentation.
  • usage: "the grandiosity of his prose"; "an excessive ornateness of language"
  • synonyms: grandiosity, magniloquence, ornateness, grandiloquence
• Loud and confused and empty talk.
  • usage: "mere rhetoric"
  • synonyms: palaver, hot air, empty words, empty talk
• Study of the technique and rules for using language effectively (especially in public speaking. ).