Entry 1 sense Webster, 1913 Sterilizer /stĕr'-əl-īzˌ-ẽr/ · Ster·il·i·zer · IPA /stˈɛrəlˌaɪzər/ 01 n. One that sterilizes anything; specif., an apparatus for sterilizing equipment or an organic fluid. 1. One that sterilizes anything; specif., an apparatus for sterilizing equipment or an organic fluid.