Entry 1 sense Webster, 1913 Accelerator /ăk-sĕl'-ẽr-ātˌ-ẽr/ · Ac·cel·er·a·tor · IPA /əkˈsɛl.əˌɹeɪ.tɚ/ 01 n. One who, or that which, accelerates. Also as an adj.; as, accelerator nerves. 1. One who, or that which, accelerates. Also as an adj.; as, accelerator nerves.