prosthesis
n. countable C1 Advanced US //ˌpɹɔsˈθɛsɪs// UK //pɹˈɒsθəsˌɪs// pros·the·sis
n. an artificial body part that replaces a missing one, like a leg or an arm. It can also mean a fake tooth or a device that helps you see or hear better.
n. an artificial replacement for a missing body part, such as a limb, tooth, or eye. In a linguistic context, it refers to the addition of a sound or syllable to the beginning of a word to make it easier to pronounce.
Via Latin, from Ancient Greek πρόσθεσις (prósthesis, “addition”), from προστίθημι (prostíthēmi, “I add”), from πρός (prós, “towards”) + τίθημι (títhēmi, “I place”), from Proto-Indo-European próti, préti + *dʰédʰeh₁ti (“to be putting, to be placing”). By surface analysis, prosth- + -esis.