Definition of "perceivable"

Every search for him was equally unsuccessful, in morning lounges or evening assemblies; neither at the Upper nor Lower Rooms, at dressed or undressed balls, was he perceivable.

1803 (date written), [Jane Austen], chapter V, in Northanger Abbey; published in Northanger Abbey: And Persuasion. […], volumes (please specify |volume=I or II), London: John Murray, […], 20 December 1817 (indicated as 1818)

The only perceivable difference between the AP and FBI photos is that the man in the FBI photo is clean-shaven and shorter-haired.

2003 January 1, “Man in Pakistan: I'm on list”, in USA Today, retrieved 2 Nov. 2008