spirometer

As a proper noun spirograph

is a geometric drawing toy consisting of a set of plastic gears and toothed rings.

As a noun spirometer is

(medicine) a device used to measure the volume of air inspired and expired by the lungs.

As nouns the difference between spirometer and respirometer

is that spirometer is a device used to measure the volume of air inspired and expired by the lungs while respirometer is a device used to measure the rate of respiration of plants.

Vitalograph is likely misspelled.

Vitalograph has no English definition.

As a noun spirometer is

a device used to measure the volume of air inspired and expired by the lungs.

Vitalogram is likely misspelled.

Vitalogram has no English definition.

As a noun spirometer is

a device used to measure the volume of air inspired and expired by the lungs.

As nouns the difference between spirometre and spirometer

is that spirometre is (nonstandard|uncommon) while spirometer is (medicine) a device used to measure the volume of air inspired and expired by the lungs.

As nouns the difference between spirogram and spirometer

is that spirogram is a graph of respiratory movement while spirometer is (medicine) a device used to measure the volume of air inspired and expired by the lungs.