verb
remain
rih-MAYN/rɪˈmeɪn/
To continue to exist, stay in a place, or be in the same state.
She remains on the bench while her companion walks away.

Etymology
The pieces express “stay behind,” which also came to mean continuing in a place or condition. In this sense, the prefix has weakened, leaving the idea of staying unchanged.
In context
the red litmus paper to remain the same in an acidic solution and a blue litmus paper to change red in an acidic solution
More examples
- Only a few questions remained unanswered.
- They have remained friends for years.
- The road will remain closed until noon.
Forms
remain · remains · remained · remaining
remainder noun — What is left after the rest is gone.