a special quality, especially one that is essential for success and is difficult to describe 特质，X 因素（尤指获得成功所必需又难以描述的素质） She certainly has the X factor that all great singers have. 她确实具备所有伟大的歌唱家所拥有的特质。 🔊🔊 The effect of the weather on production costs is always something of an X factor, or unknown variable. 天气对生产成本的影响始终是X因子或未知变量。