🔼The name Nohah in the Bible
There's only one Nohah in the Bible. He is the fourth of five sons of Benjamin, according to 1 Chronicles 8:2. The genealogy of Benjamin of Genesis 46:21 lists ten sons but no Nohah (among others). In Numbers 26:38-39 Benjamin has five sons but no Nohah. And in 1 Chronicles 7:6, Benjamin has three sons (and no Nohah).
These discrepancies are not as detrimental as may seem. From what we may gather from the text, ancient genealogies were the result of oral traditions but recent ones (those set in the time in which they were written down) were established from counting contemporary clans according to their respective name-giving patriarchs. Nohah may have been a distant descendant of Benjamin, whose generations of progeny called themselves Nohahites, who were around and acknowledged when the Chronicler asked them about their lineage: we are sons of Nohah, son of Benjamin.
The progeny of Naaman, for instance, who is Benjamin's fifth son according to Genesis 46:21, was apparently too insubstantial to remain a clan on its own, and was, what seems, assimilated by the people of Bela, Benjamin's first born son (Numbers 26:40). And Rosh (son number seven, according to Genesis 46:21) either died childless, or his lineage died out or "daughtered out" as the geneticists say, or his remnant was namelessly assimilated into another tribe. Whatever it was, Rosh is mentioned no further.
🔼Etymology of the name Nohah
The name Nohah appears to be a feminine form of an otherwise unused noun derived of the verb נוח (nuah), meaning to rest:
For a meaning of the name Nohah, NOBSE Study Bible Name List reads Rest. Jones' Dictionary of Old Testament Proper Names, curiously, omits this name. BDB Theological Dictionary does not interpret the name Nohah, but does list it under the verb נוח (nuah), meaning to rest.