k stands for potassium...its complexed with penicillin....mainly added with phenoxymethylpenicillin.so that a potassium sparing diuretic need not be used.
The "K" in "K-Mart" comes from the company's founder, Sebastian Spering Kresge, who opened his first store in 1899. The stores were called "Kresge" until 1962 when they adopted the "K-Mart" name.
401k is a section of the US Tax Code which describes a particular retirement plan. Section 401a describes a different plan. The letter is a subsection of chapter 401 of the Tax Code.