means Animal dung and other organic matter spread on land to fertilize crops and enrich the soil.

from From Anglo-French 'mainoverer' and Old French 'manouvrer,' meaning to work with the hands — the same root that gives us 'maneuver.' It once simply meant to till or cultivate land by hand; only later did the word narrow to the stuff you spread while doing so. So 'manure' and 'maneuver' are siblings, both tracing back to Latin 'manu operari' (to work by hand) — one ended up in boardrooms, the other in barnyards.