ではないか Grammar translation

Question

what does

ではないか

mean in the sentence below? And can someone please translate it?

耳に馴染みのない方も多いのではないかと思いますが、 (after that he explains the word)....

Answer 1

A は B ではないか is asking "isn't A (=) B?", and here used as a (stylized) rhetorical question, i.e. meaning "I think that A is B".

Since A と思いますが is "I think that A, but ...", we are also dealing with an ellipsis (assuming you're quoting the whole sentence).

In any case, both figures of speech are very commonly used in Japanese.

Unfortunate for a straight-forward translation is that basically both parts translate to "I think that". In English, we can try to translate it like

耳に馴染みのない方も多いの ではないか¹ と思いますが **…**²
I think that a number of people might¹ not be familiar with [this] **…**²