a meeting of minds or a tacit mutual understanding, especially referring to the exchange of romantic feelings

他们两人心有灵犀，一个眼神就能明白对方的心意。

a rhinoceros horn, traditionally reputed to possess a white vein connecting the two ends and conferring telepathic or supernatural powers

古人常将犀角视为通灵的神物，称之为灵犀。