-fold
/fəʊld/suffix
forming adjectives and adverbs from cardinal numbers ［附于基数后构成形容词和副词］
1
- in an amount multiplied by表示“倍”, “重”：
threefold.
2
- consisting of so many parts or facets表示“由若干部分（或面）组成”：
twofold.
词源
Old English -fald, -feald; related to FOLD1.