Definitions of suggestion:

• noun:   the sequential mental process in which one thought leads to another by association
• noun:   an idea that is suggested

  Example: "The picnic was her suggestion"

• noun:   a proposal offered for acceptance or rejection

  Example: "It was a suggestion we couldn't refuse"

• noun:   persuasion formulated as a suggestion
• noun:   the act of inducing hypnosis
• noun:   a just detectable amount