3 syllables:
monitor, sonneter

4 syllables:
admonitor, al-monitor, heart monitor, markmonitor, recognitor, uss monitor

5 syllables:
anti-monitor, multi-monitor

6 syllables:
african monitor, cardiac monitor

9 syllables:
electronic fetal monitor

3 syllables:
polisher, chronicler, moniker, cottager, oliver, omnivore, shoplifter, sonneteer, machmeter, alcazar, almoner, blockbuster, bolivar, cocklebur, colander, columnar, commissar, commodore, commoner, common murre, conifer, globular, gobbler, godmother, gospeler, gospeller, gossamer, gossiper, groveller, hollander, holloware, hosteller, jocular, modeler, monomer, nodular, ocular, onager, polymer, pompadour, popular, promiser, promisor, quadrature, slopseller, sodbuster, swashbuckler, troposphere, wobbler

4 syllables:
depositor, discomfiture, compositor, photometer, barometer, geometer, admonisher, algometer, assam rubber, astrologer, astronomer, atmometer, bilocular, binocular, biographer, black hollander, chronometer, copolymer, cosmographer, demographer, dock-walloper, ethnographer, femtometer, geographer, hectometer, hodometer, horologer, hydrometer, hygrometer, involucre, kilometer, lithographer, micrometer, odometer, pedometer, philosopher, photographer, picometer, pisanosaur, pornographer, psychrometer, pyrometer, sclerometer, spectrometer, speedometer, spherometer, subocular, tachometer, thermometer, tintometer, typographer, unpopular, viscometer

5 syllables:
tensiometer, air thermometer, anemometer, audiometer, bibliographer, choreographer, craniometer, declinometer, densitometer, dynamometer, electrometer, eudiometer, gas thermometer, goniometer, inclinometer, interlocutor, lexicographer, magnetometer, mass spectrometer, meat thermometer, mileometer, oceanographer, piezometer, press photographer, radiographer, radiometer, refractometer, salinometer, sensitometer, simon bolivar, tacheometer, variometer, vinyl polymer

6 syllables:
accelerometer, autobiographer, beckman thermometer, candy thermometer, cinematographer, cubic kilometer, evaporometer, historiographer, interferometer, oven thermometer, platinum thermometer, potentiometer, silicone polymer, telethermometer, thermohydrometer

7 syllables:
mercury barometer, centigrade thermometer, clinical thermometer, electric thermometer, fahrenheit thermometer, mercury thermometer, political commissar, radiomicrometer, resistance thermometer, reversing thermometer, vernier micrometer

8 syllables:
electrodynamometer

9 syllables:
radio interferometer

11 syllables:
maximum and minimum thermometer