Medical Definition of expression
1a: something that manifests, represents, reflects, embodies, or symbolizes something else <the first clinical expression of a disease>b: the detectable effect of a gene; also : the sum of the processes (as transcription and translation) by which a gene is manifested in the phenotype <gene expression can be controlled by regulatory proteins that bind to specific sites on DNA—Mark Ptashne>: expressivity
2: facial aspect or vocal intonation as indicative of feeling
3: an act or product of pressing out
Seen and Heard
What made you want to look up expression? Please tell us where you read or heard it (including the quote, if possible).