覆盖
fù gài · HSK 7
to cover
🛌 覆 = cover/overturn + 盖 = lid; together: lid-over = to cover
覆 carries the sense of overturning or draping over; 盖 is a lid or cover. The compound stacks two cover-words for emphasis: to cover, blanket, or overlay something completely.
盖 — grass 艹 + 盍 (cover/lid)
Originally written 葢, this character combines the grass radical 艹 with 盍 ('to cover'), which itself shows a lid over a vessel. It first referred to a thatched grass cover or lid, then broadened to mean 'to cover' generally, and later extended to surnames and the conjunction 'thereupon'.