to undergo back mutation.
in genetics, to revert to a former non-mutated condition
- Back mutation
a mutation of an existing mutant gene that restores it to its previous form. noun (genetics) the reversion of a mutant to the original phenotype noun See reverse mutation
- Back nine
the final nine holes on an eighteen-hole course.
- Back number
an out-of-date issue of a serial publication. Informal. anything out-of-date. Historical Examples If I’ve got to be a back number I want to romp right back far enough to have some fun out of it. At Good Old Siwash George Fitch If I have I’m a back number—and I’d a great deal rather be dead. […]
- Back o’ beyond
remote; out-of-the-way; isolated.