Superplurality

I was programming today and I realized that there is a very common naming issue I encounter, which is that of naming variables that are 'lists of lists of something'.

For example I might have an 'embedding' object, which I put into a an 'embeddings' list, which in turn I put into a another list, as illustrated by the pseudocode:

    embeddings_ = []
    for X in Y:
        embeddings = []
        for embedding in X:
            embeddings.append(embedding)
        embeddings_.append(embeddings)

I wonder, what are your thoughts on naming such 'superplural' entities? In the past I have sometimes used an underscore like in the example above, or another suffix like '_list'. The paper I link to has another suggestion: 'embeddingses'. Other times we get lucky and there is actually a proper term for the 'list of lists' objects, for example, a list of lists of pixels is an image [1].

[1] This analogy makes me realize that 'superplurality' might also be seen as n-dimensionality, in the sense that a pixel is 0-d, a list of pixels is 1-d, an image is 2-d and, going further, a list of images (like a video) can be interpreted as 3-d.