This is the 8284th most frequent German word.
jota
The German word "Jota" refers to the smallest amount or a tiny bit, similar to "iota" in English.
Here, "Jota" signifies not even the smallest element, emphasizing the complete lack of truth in the book.
Das Buch enthält nicht ein Jota Wahrheit.
The book contains not an iota of truth.
In this context, "Jota" expresses a deficiency, emphasizing that the speech was completely devoid of interest.
Seine Rede war nirgends ein Jota interessant.
His speech was not even an iota interesting anywhere.
This sentence uses "Jota" metaphorically to mean a very small amount or detail.