A gene encoding an essential protein that regulates circadian rhythm, normally written in italics: timeless.
"In fruit flies, the timeless gene plays a crucial role in maintaining their internal clock by regulating circadian rhythms."
In plain English: A timeless person is someone who never changes their style or attitude no matter how much time passes.
"The timeless became his favorite way to describe classic stories that never go out of style."
Usage: Use this term exclusively in scientific contexts when referring to the specific Drosophila clock gene; avoid using it as a general adjective for enduring style or fashion. Do not capitalize it unless beginning a sentence, even though it is derived from a proper noun context in genetics.
Eternal.
"The ancient stone monument stands as a timeless testament to humanity's enduring hope, untouched by the passage of centuries."
The word timeless is formed by combining the root time with the suffix -less, which means without or lacking something. It entered English as a straightforward compound to describe anything that exists outside of temporal limits.