jī is literary. Two related senses, both about being minced fine. (1) Food: a paste or pickle of finely chopped ginger, garlic, or pickled vegetable, once the staple condiment of impoverished students and monks. The phrase
朝齑暮盐 'minced pickle by morning, salt by evening' (from Han Yu's 《
送穷文》) names a life of scholarly poverty. (2) Figurative: smashed to bits, ground to powder.
齑粉 'minced powder' = completely pulverised, as in
化为齑粉 'turned to dust'.