Noun pigweed has 3 senses

• pigweed(n = noun.plant) chenopodium album, lamb's-quarters, wild spinach - common weedy European plant introduced into North America; often used as a potherb; Array
has parts: lamb's-quarter, pigweed, wild spinach, wild spinach
is a kind of goosefoot

• pigweed(n = noun.plant) amaranthus hypochondriacus - leaves sometimes used as potherbs; seeds used as cereal; southern United States to Central America; India and China; Array
is a kind of amaranth

• pigweed(n = noun.food) lamb's-quarter, wild spinach - leaves collected from the wild; Array
is a kind of green, greens, leafy vegetable
is a part of chenopodium album, lamb's-quarters, pigweed, wild spinach