Ilsa is a German feminine given name, functioning as a variant of Ilse. Ilse itself is a German and Dutch diminutive of Elisabeth, which ultimately derives from the Hebrew name ʾElishevaʿ, meaning "my God is an oath." The name thus shares the rich biblical heritage of Elizabeth, borne in the Old Testament by Elisheba, wife of Aaron, and in the New Testament by Elizabeth, mother of John the Baptist. While Ilsa is most familiar to English-speaking audiences through the character Ilsa Lund in the classic film Casablanca, its usage as a given name remains primarily German. The name's connection to the lineage of Elizabeth places it among a vast family of variants across languages, including English Elizabeth, Basque Elixabete, and Armenian Zabel. Meaning: "my God is an oath" (via Elizabeth) Origin: Germanic variant of Ilse, ultimately from Hebrew Type: Diminutive/variant Usage regions: German-speaking countries