释义
n.
a secure refuge, especially a place well protected by natural features
（尤指受天然地貌保护的）安全处所
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a remote Himalayan mountain fastness .喜马拉雅山山间的一个僻静去处。
[mass noun]the ability of a material or dye to maintain its colour without fading or washing away
（材料或染料的）色牢度不褪色性
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the dyes differ in their fastness to light .这些染料在光照下的不褪色性各不相同。
词源
"Old English