This will be my house rules, such as they are.
1) Reaction mass, such as liquid or solid rockets.
2) Stutterwarp drive:
FreeLance Traveller Stutterwarp drive
3) Lyman Drive
FreeLance Traveller Lyman Drive
4) The book calls it the Epstein drive. Maybe I'll call it George. "Let George do it." or "George isn't working today. We will have to call for help." or "George is our Pal."