percomorph liver oil
noun
per·co·morph liver oil
| \ ˈpər-kə-ˌmȯrf-
\
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Medical Definition of percomorph liver oil
: a fatty oil that is obtained from the fresh livers of bony fishes of an order (Percomorphi) including perches, basses, mackerels, and numerous related forms and that is administered to infants as a source of vitamins A and D