“结婚适龄”常见的英文表达是 “of marriageable age” 。
例如：In some cultures, people are expected to get married when they are of marriageable age.（在一些文化中，人们被期望在达到结婚适龄时结婚。 ）
此外，也可以用 “at the appropriate age for marriage” 来表达类似意思。例如：He has reached the appropriate age for marriage but hasn't found the right person yet.（他已经到了结婚适龄，但还没找到合适的人。 ）