Mound radical on the left —
阝 on the left is
阜 (hill, earthwork).
队 is the simplified form of
隊, originally meaning a 'fall from a mound', and by extension a tumbling group of soldiers, hence a squad or detachment. Joins the hillside family:
阴,
阳,
险,
防 (defend). The radical preserves the original mound-of-soldiers image.
