MR1 or MR-1 may refer to: Bristol M.R.1, an experimental biplane HAWAII MR1, a sea floor imaging system Major histocompatibility complex, class I-related Mercury-Redstone 1, an unsuccessful unmanned American space mission PNKD, or myofibrillogenesis regulator 1 Shewanella oneidensis MR-1, a bacterium Hadoop architecture Map/Reduce version 1 Beijing–Nanning–Hanoi through train