A diminutive form of “father”, similar to English “daddy” (Ety/ATA). Helge Fauskanger suggested it may have developed from primitive ✱✶attō based on its Quenya equivalent ᴹQ. atto (AL-Ilkorin/adda), but I think that is likelier to be a child’s invention, unrelated to other languages.
noun. father (hypocoristic)
- ᴹQ. atto “father (hypocoristic)” ✧ Ety/ATA