first-born

n, adj [attrib 作定语] (dated 旧) (child) born before other children; eldest （孩子中）头生的; 长子或长女: their first-born son 他们的长子.

first aid, first and foremost, first balcony, first base, first class, first cousin, first degree, first finger, first floor, first gear, first lady, first name, first night, first of all, first offender, first officer, first or last, first refusal, first school, first-aid, first-class, first-day cover, first-footing, first-fruit, first-hand, first-rate, firsthand, firstly, firth, fiscal, fiscal year, fish, fish and chips, fish cake, fish finger (US fish stick), fish out, fish pond, fish weir, fish-eye lens, fish-farm,