2 syllables:
for its, mauritz, moretz, nor its, orates, oritz, or its

3 syllables:
before its, explore its, igorots, restore its

2 syllables:
terrace, cirrus, doris, ferrous, horus, virus, aurous, cyrus, purus, gyrus, peeress, heiress, pyrus, torus, morris, laurus, starets, morus, chorus, merits, taurus, porous, sorus, iris, carrots, ceras, cuirass, larus, parus, pirates, purace, pyrrhus

3 syllables:
acarus, thesaurus, nereus, honduras, slow virus, millionairess, effloresce, embarrass, liquorice, polaris, desirous, sciurus, high spirits, arcturus, ichorous, belarus, acorus, ailurus, atherurus, baccharis, bos taurus, botaurus, centaurus, corchorus, dutch iris, dwarf iris, greek chorus, hesperis, in chorus, lathyrus, leonurus, low spirits, luvarus, lyrurus, micrurus, necturus, paliurus, papyrus, petaurus, pipturus, plant virus, psithyrus, pylorus, quakeress, seiurus, silurus, tapirus, triturus

4 syllables:
pythagoras, ardent spirits, retrovirus, brontosaurus, polyporus, myxovirus, herpes virus, disembarrass, stegosaurus, bearded iris, tumor virus, neutral spirits, allosaurus, ameiurus, ankylosaurus, automeris, barosaurus, bulbous iris, byelarus, callisaurus, camptosorus, cistothorus, conilurus, cyclosorus, dasyurus, dinoceras, dipsosaurus, echovirus, english iris, genus iris, german iris, hadrosaurus, hydrocharis, hydrochoerus, in good spirits, in high spirits, in low spirits, menticirrhus, nigroporus, ocyurus, ophisaurus, palinurus, parvovirus, persian iris, phylloporus, plesiosaurus, pleurosorus, polyborus, polycirrus, raphicerus, reovirus, rhabdovirus, sceloporus, seismosaurus, smallpox virus, spanish iris, sternotherus, stinking iris, tetrapturus, thryothorus, undesirous, urosaurus, vernal iris, xenosaurus, yellow iris

5 syllables:
tyrannosaurus, apatosaurus, ichthyosaurus, japanese iris, picornavirus, british honduras, ebola virus, actinomeris, alepisaurus, alopecurus, animal virus, ceratosaurus, chlamydosaurus, corythosaurus, dalmatian iris, deinocheirus, edaphosaurus, edmontosaurus, eleocharis, florentine iris, herrerasaurus, megalosaurus, oligoporus, paradoxurus, pisanosaurus, poliovirus, psittacosaurus, staurikosaurus, styracosaurus, titanosaurus, wound tumor virus

6 syllables:
herpes simplex virus, genus brontosaurus, genus stegosaurus, herpes zoster virus, judgement on the merits, judgment on the merits, orthomyxovirus, paramyxovirus, tamiasciurus

7 syllables:
hepatitis a virus, cytomegalovirus, genus tyrannosaurus, pachycephalosaurus

8 syllables:
tobacco mosaic virus, human papilloma virus

11 syllables:
human immunodeficiency virus