What is the meaning of Acinus?

One of the small grains or drupelets which make up some kinds of fruit, as the blackberry, raspberry, etc.

A grape-stone.

One of the granular masses which constitute a racemose or compound gland, as the pancreas; also, one of the saccular recesses in the lobules of a racemose gland.

a berry, especially the grape.

the seed of a berry.

Source: wiktionary.org