[1] : The Collaborative International Dictionary of English v.0.48

perceptible \percep"tible\ p~erse^p"ti^b'l, a. l.
   perceptibilis: cf. f. perceptible. see perceive.
   capable of being perceived; cognizable; discernible;
   perceivable; large enough to be perceived; not so small as to
   be incapable of perception.
   1913 webster

         with a perceptible blast of the air.     --bacon.
   1913 webster -- percep"tibleness, n. --
   percep"tibly, adv.
   1913 webster
see also:
perceive percep"tibleness percep"tibly 

[2] : WordNet (r) 2.0

perceptibly
     adv : in a noticeable manner; "he changed noticeably over the
           years" syn: noticeably ant: imperceptibly
see also:
noticeably imperceptibly 

[3] : Moby Thesaurus II by Grady Ward, 1.0

32 moby thesaurus words for "perceptibly":
   apparently, appreciably, clearly, conspicuously, definitely,
   discernibly, distinctly, evidently, explicitly, expressly,
   glaringly, manifestly, markedly, measurably, noticeably,
   observably, obviously, palpably, patently, perceivably, plainly,
   prominently, pronouncedly, recognizably, seeably, staringly,
   starkly, unconcealedly, undisguisedly, unmistakably, visibly,
   with clarity

Perceptibly >> P Words
Perceptibly, definition of term: Perceptibly
perceptibly_pag1.html