an estimate of a number or an amount that is almost correct, but not exact 近似值◆That's just an approximation, you understand. 你知道那只不过是近似值。
a thing that is similar to sth else, but is not exactly the same 类似事物◆Our results should be a good approximation to the true state of affairs. 我们的结果应该与实际情况非常接近。