This parameter determines the number of threads used to copy map outputs to the reducer, 5 by default.

这个参数决定把 map 输出复制到 reduce 所使用的线程数量，默认值是 5。

youdao

The Beatus map of 1109, a copy of one from 776, includes such a continent beyond the Red Sea.

ECONOMIST: Modern man knows where he stands. His map tells him

What kinds of news organizations tend to be big, have lots of writers and bureaus all over the map, use formal language with high standards of copy editing, and have been around long enough to have established reputations?

FORBES: Why Publishers Need to Stop Worrying and Learn to Love Google