son ‧ o ‧ gram /ˈsɒnəɡræm $ ˈsɑː-/ BrE AmE noun [countable] American English technical
[ Date: 1900-2000 ; Language: Latin ; Origin: sonus ( ⇨ ↑ sound 1 ) + English -gram ]
an image, for example of an unborn baby inside its mother’s body, that is produced by a special machine SYN ultrasound British English