• A clinical finding in which there is loud or harsh inspiratory noise associated with obstruction of the upper airway.
  ACC/AHA Clinical Data Terminology
  American College of Cardiology and American Heart Association , 2020
• A high-pitched breath sound secondary to obstruction and turbulent air flow at the level of the larynx.
  NICHD Pediatric Terminology
  U.S. National Cancer Institute, 2021
• A symptom resulting from laryngeal obstruction. It is characterized by a high pitched breathing sound.
  NCI
  U.S. National Cancer Institute, 2021
• Stridor is a high pitched sound resulting from turbulent air flow in the upper airway.
  Human Phenotype Ontology (HPO)
  The Human Phenotype Ontology Project, 2025
• A disorder characterized by a high pitched breathing sound due to laryngeal or upper airway obstruction.
  Common Terminology Criteria for Adverse Events
  U.S. National Institutes of Health, 2021
• Stridor is a high-pitched, predominantly inspiratory sound. It is most commonly associated with acute disorders, such as foreign body aspiration, but can be due to more chronic disorders, such as tracheomalacia.
  Merck Manuals
  Merck & Co., Inc., 2025
• Stridor is an abnormal, high-pitched sound produced by turbulent airflow through a partially obstructed airway at the level of the supraglottis, glottis, subglottis, or trachea. Its tonal characteristics are extremely variable (ie, harsh, musical, or breathy); however, when combined with the phase, volume, duration, rate of onset, and...
  Medscape
  WebMD, 2025