https://doi.org/10.1351/goldbook.H02880
Compounds, $\ce{RC(NHNH2)2=NNH2}$, derived from carboxylic acids by replacing $\ce{–OH}$ by $\ce{–NHNH2}$ (or N-substituted analogues) and $\ce{=O}$ by $\ce{=NNH2}$ (or substituted analogues). A specific hydrazidine is named as a hydrazide hydrazone, e.g. hexanohydrazide hydrazone.