You searched for: “yg
yoctogram, yg
The metric unit of 1.7 yg is equal to the mass of a proton or neutron.
yottagram, Yg
1. One yottagram, approximately the "mass of water in the Pacific Ocean".
2. Mass of earth equal to about 6 000 yottagram.
— Source for this and other yotta words: Chemistry and Molecular Biology Resources,
UC Extension, Berkeley/San Francisco