neonate
/ˈniːəʊneɪt/noun
1- a newborn child or mammal新生儿; 新出生的哺乳动物。
1.1
- Medicine an infant less than four weeks old【医】（不满四周的）新生儿。
词源
1930s: from modern Latin neonatus, from Greek neos 'new' + Latin nat- 'born' （from the verb nasci）.