Etymology: < galacto- comb. form + -meter comb. form2, probably after French galactomètre (1796 or earlier). Compare German †Galactometer (1818 or earlier; now Galaktometer). Compare earlier lactometer n. Now rare.
An instrument or device used to measure the specific gravity or fat content of milk; = lactometer n.
1826 Gardener's Mag. 1 204 Lactometer... Sold in Paris by the opticians under the name of galactometer.
1853 A. Ure Dict. Arts (ed. 4) I. 838 When our purpose is to determine the quality of cream, the galactometer may consist merely of a long graduated glass tube standing upright.
1897 N. Straus Let. 22 Mar. in L. G. Straus Dis. in Milk (1913) 46 Samples of..milk, perfectly good according to all the customary tests of color, taste, smell, and the galactometer.
1906 T. S. Westcott tr. F. Frühwald Ref. Handbk. Dis Children 314 (caption) Galactometer for testing milk as sold in the market.