from The American Heritage® Dictionary of the English Language, 4th Edition
- n. Any of the substances present in the nucleus of a cell, consisting chiefly of proteins, phosphoric acids, and nucleic acids.
from the GNU version of the Collaborative International Dictionary of English
- n. A constituent of the nuclei of all cells, containing protein and nucleic acid. It is a colorless amorphous substance, readily soluble in alkaline fluids and especially characterized by its comparatively large content of phosphorus. It also contains nitrogen and sulphur.
from The Century Dictionary and Cyclopedia
- n. The phosphorized nitrogenous constituent of cell-nuclei.
From German Nuclein, corresponding to nucleus + -in. (Wiktionary)