(inorganic chemistry) Containing both cobaltous and cobaltic ions e.g. cobaltosic oxide, Co₃O₄

(biochemistry) Relating to thanatochemistry

A letter or written communication that serves to introduce an accompanying document; especially, a letter that introduces a résumé or curriculum vitae.

(countable) A socially tactless or awkward act. / (uncountable) Lack of tact; tactlessness; awkwardness.