biosimilar Pronunciation: /bʌɪə(ʊ)ˈsɪmɪlə/Definition of biosimilar noun a biopharmaceutical drug designed to have active properties similar to one that has previously been licensed:copycat drug makers use an innovator’s research data to make biosimilarsOrigin: early 21st century: from bio- + similarbiosimilar in other Oxford dictionaries Definition of biosimilar in the US English dictionary