phocomelia n an abnormality of development in which the upper part of an arm or leg is missing so the hands or feet are attached to the body like stumps; rare condition that results from taking thalidomide during pregnancy Usage(s) Lenz answered that thalidomide has been shown to cause phocomelia in rhesus and other monkey species in which the condition does not occur naturally. It consisted of assorted internal malformations in newborn babies, plus an upsurge in one hitherto rare condition: phocomelia or "seal limbs. Synonym(s) seal limbs