Douglas Harper's Etymology Dictionary
1947, from nucleus + -ide.
Wiktionary
n. (context physics English) An atomic nucleus specified by its atomic number and atomic mass.
Wikipedia
A nuclide (from nucleus) is an atomic species characterized by the specific constitution of its nucleus, i.e., by its number of protons Z, its number of neutrons N, and its nuclear energy state.
The word nuclide was proposed by Truman P. Kohman in 1947. Kohman originally suggested nuclide as referring to a "species of nucleus" defined by containing a certain number of neutrons and protons. The word thus was originally intended to focus on the nucleus.
Usage examples of "nuclide".
To ascertain the suitability of the Fioneriska rock formations for the storage of radio nuclides with decay half-lives in excess of one million years, as suggested, further deep drilling operations would be required.
Almost every element had some radioactive nuclides, leftover hash from the Creation.
There are other radioactive nuclides that have half-lives a hundred times longer.
The half-life of the nuclides was less than ten years, but Horstmann would be too hot to touch for at least another century.