What is the meaning of interrogative?

noun

• A sentence of inquiry that asks for a reply.
  • usage: "he asked a direct question"; "he had trouble phrasing his interrogations"
  • synonyms: question, interrogation, interrogative sentence
• Some linguists consider interrogative sentences to constitute a mood.
  • synonyms: interrogative mood

adjective

• Relating to verbs in the so-called interrogative mood.
  • usage: "not all questions have an interrogative construction"
• Relating to the use of or having the nature of an interrogation.
  • synonyms: interrogatory