Definitions of normal:

• noun:   something regarded as a normative example
• adjective:   conforming with or constituting a norm or standard or level or type or social norm; not abnormal

  Example: "Serve wine at normal room temperature"

• adjective:   being approximately average or within certain limits in e.g. intelligence and development

  Example: "A perfectly normal child"

• adjective:   in accordance with scientific laws
• adjective:   forming a right angle