protium

also defines: protide, protio
https://doi.org/10.1351/goldbook.P04903
A specific name for the atom $\ce{^{1}H}$. The cation $\ce{^{1}H^{+}}$ is a proton, the species $\ce{1H}$ is a protide anion, and $\ce{1H}$ is the protio group. The word proton should not be used for $\ce{H^{+}}$ in its natural abundance.
Source:
PAC, 1988, 60, 1115. (Names for hydrogen atoms, ions, and groups, and for reactions involving them (Recommendations 1988)) on page 1116 [Terms] [Paper]