Wiktionary
n. (context biology English) Any measurable phenomenon that indicates the presence of life
Wikipedia
A biosignature is any substance – such as an element, isotope, molecule, or phenomenon – that provides scientific evidence of past or present life. Measurable attributes of life include its complex physical and chemical structures and also its utilization of free energy and the production of biomass and wastes. Due to its unique characteristics, a biosignature can be interpreted as having been produced by living organisms; however, it is important that they not be considered definitive because there is no way of knowing in advance which ones are universal to life and which ones are unique to the peculiar circumstances of life on Earth. Nonetheless, life forms are known to shed unique chemicals, including DNA, into the environment as evidence of their presence in a particular location.
Usage examples of "biosignature".
It was due to pass us in thirty years or so, there wasn’t a danger of collision…but a Starfleet probe had brought back data concerning a unique biosignature located within the comet, a biosignature that closely resembled that of a joined Trill.
They didn’t know that the Trill are a joined species, of course, didn’t understand what they’d found, but we knew immediately—Starfleet had detected the biosignature of a symbiont.
Jayvin and Doctor Jaurez checked readings, directing our pilot to where the biosignature was strongest, somewhere beyond the mouth of one of the larger caves.
Tuvok’s biosignature was emanating from deep within that central structure.
La Forge looked in to see the distinctive biosignature of William Riker seated comfortably in the large chair in the common room, just a couple of meters from the poker table.
He had Shar’s biosignature on file, so he gave it and the tracer frequency to the Harbortown police to help them track you.