1630s, "reason, rationale," from Latin ratio "reckoning, numbering, calculation; business affair, procedure," also "reason, reasoning, judgment, understanding," from rat-, past participle stem of reri "to reckon, calculate," also "think" (see reason (n.)). Mathematical sense "relationship between two numbers" is attested from 1650s.
双语例句
1. In 1978 there were 884 students at a lecturer/student ratio of 1:15.
1978年有884名学生，师生比为1比15。
来自柯林斯例句
2. The adult to child ratio is 1 to 6.
成人与儿童的比例为1比6。
来自柯林斯例句
3. What is the ratio of men to women in the department?
这个部门的男女比例是多少？
来自《权威词典》
4. The ratio of pupils to teachers was 30 to 1.
学生和老师的比率是30比1.
来自《简明英汉词典》
5. The ratio between the two sides is one to four.