Amrod's father-name was Pityafinwë, or "Little Finwë", as he was the youngest of the House of Finwë (debatably; Tolkien wavered on this point). The short form of his name was Pityo, "Little One". His mother-name was Ambarussa ("top-russet", referring to his hair). His twin Amras shared the same mother-name for a time (see Amras for further information).
Amrod seems like the Sindarization of Ambaráto although it was the name of his cousin Aegnor.
Twin brother of Amras and youngest(?) of the sons of Fëanor (it is unclear which of the twins was born first). The name is a compound of am “up” and the suffixal form -rod of raud “lofty, noble” (PM/353, VT41/10), an adaption of his Quenya name Q. Ambarto (PM/353).
Conceptual Development: In the earliest Lost Tales, this character was first named G. Damrod (LT2/251), and the name remained N. Damrod in Silmarillion drafts from the 1930s (LR/223). It appeared in The Etymologies with the gloss “hammerer of copper”, a combination of N. dam “hammer” and the lenited form of N. rhaud “metal” (Ety/NDAM, RAUTĀ).
The name was changed to S. Amrod in Silmarillion revisions from the 1950s-60s (WJ/197). Elsewhere Tolkien said that Amrod would also have been the proper Sindarin adaption for the name of Ambarto’s cousin Q. Ambaráto, but that Noldorin Elf chose the Sindarin name Aegnor instead (PM/347).