A more clinical or formal term for an infant, often used in medical or official contexts. みどりご carries a softer, more literary nuance.
Etymology
The word みどりご is composed of みどり (green, verdant) and 子 (child). The exact origin is uncertain, but it may derive from the image of a newborn as fresh and new like young greenery. The kanji 嬰児 uses 嬰 (infant) and 児 (child), which are direct but rare characters for this meaning.
