Ilka is of German origin, meaning "the whole" or "complete." It's a variant spelling of the German name Ilse, which itself derives from the Old High German word 'aliz' meaning "noble." The name Ilka gained popularity in Germany during the late 19th and early 20th centuries. It is often associated with the works of German author Heinrich Mann, who featured a character named Ilka Rosendahl in his novel "Professor Unrat" (also known as "The Blue Angel"). In recent years, it has seen renewed interest in Germany and other German-speaking countries.
"The name Ilka saw its peak popularity between 1966 and 1970, with a high of 19 births in 1970. However, it experienced a steady decline thereafter, with the last notable year being 1981, after which it remained consistently low until 1992."