ul‧tra‧sound /ˈʌltrəsaʊnd/
noun1. [uncountable] sound that is too high for humans to hear
2. [uncountable and countable] a medical process using this type of sound, that produces an image of something inside your body:
investigation of the liver by ultrasound An ultrasound scan revealed that the baby was a boy. [TahlilGaran] Dictionary of Contemporary English ▲