hydrometer
hy.drom.e.ter or hy.dro.met.ri.cal \hi--'dra:m-*t-*r\ \.hi--dr*-'me-trik\ \-tri-k*l\ \hi--'dra:m-*-tre-\ n : a floating instrument for determining specific gravities of liquids and hence the strength (as of spirituous liquors, saline solutions) - hy.dro.met.ri.c aj