jizz
n.— «In both the examples cited above, the digital camera would never even have been used if the observers had not realized they were seeing something different, an odd Olivaceous or suspect sunbird. That knowledge only comes from experience in the field with the bird, mammal, dragonfly—or whatever—right in front of you. This experience is the only way to become aware of what is called in naturalist parlance “jizz.” Jizz is the collection of definable and indefinable characteristics—visual, behavioral or vocal—that go together to give a species its particular character. With experience and familiarity it is possible to identify by jizz alone and, perhaps more important, to know when something is different and possibly new and exciting.» —“Back to Basics” by Richard Hoath Egypt Today (Cairo) Sept., 2006. (source: Double-Tongued Dictionary)