monorail
noun
- transportation system with a single rail
Wiktionary
Pronunciation: /ˈmɑnəɹeɪl/ / /ˈmɒnəɹeɪl/ / /ˈmɒnəʊˌɹeɪl/
noun
Etymology: Borrowed from French monorail, equivalent to mono- + rail.
- a railroad system where the trains run on one rail
- a train running on a single rail