胎次的英文：
parity

parity check digit
奇偶校验位

2 and 16 have the same parity.
2和16有相同的奇偶性。

This classification is called the parity of the permutation analogous to the definition of parity of integers.
这种分类叫作置换的奇偶性，类似于整数偶性的定义。

Italy wanted naval parity with France.
意大利想要在海军实力上与法国平起平坐。

Silver can be raised by law to a parity with gold in value.
银可由法律提高到和金同等的价值。