Some words are harder to pinpoint. There’s a scientific meaning which requires more than a dictionary, it requires a scientific dictionary. But for some writers where science is not their subject why bother?
Because the words prop up from time to time in unrelated materials and publications and you just got know the meaning. I think a broad definition may suffice on google search, but it prompts one to go further. Yet for many unspecialized writers a broad definition may give enough information to work on.