Sentence:  Their smallest lobules were called <WSD>acini</WSD>, a term which has also been used to denote the saccular recesses in the lobules ... 
Meaning of the word marked with <WSD> tags:  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.