🔼The name Tanhumeth in the Bible
There's only one Tanhumeth in the Bible, and he's mentioned twice. Tanhumeth the Netophathite is the father (or, as some scholars contest, the mother) of Seraiah, who was among the men who joined Ishmael son of Nethaniah in their little revolt against Gedaliah, the governor of Judah in service of Babylon (2 Kings 25:23, Jeremiah 40:8). Gedaliah initially manages to calm everybody down and send them on their way, but Ishmael returns later and kills Gedaliah anyway.
🔼Etymology of the name Tanhumeth
The name Tanhumeth appears to be derived from the noun תנחום (tanhum), meaning consolation, which in turn comes from the verb נחם (naham), meaning to be sorry or compassionate:
The reason why some scholars believe that this Tanhumeth was Seraiah's mother is that the name Tanhumeth is a feminine plural of a word that otherwise only exists as a masculine plural (תנחומים). It's of course entirely possible that Tanhumeth was a woman, but it's not explicitly mentioned, and that makes it dubious. And names in the old Hebrew world often didn't refer to the person that bore them but rather to something else (a happening, a general concept, a phenomenon).
There are many males in the Bible that have names that are actually feminine nouns, and vice versa. The name Tanhumeth sticks out because we only know this noun to be used in the masculine form, and that seems to point at the femininity of Tanhumeth. But on the other hand, there are many nouns that exist in masculine and feminine forms, and it might be that the name Tanhumeth reflects a perfectly valid feminine form of a noun that existed in ancient Hebrew but simply never made it into the extant texts of the Bible.
For a meaning of the name Tanhumeth, both NOBSE Study Bible Name List and Jones' Dictionary of Old Testament Proper Names read Consolation. BDB Theological Dictionary does not interpret our name but does list it under the verb נחם (naham), meaning to be sorry or compassionate.