pigweed

noun

1. any goosefoot of the genus Chenopodium, especially C. album.
2. any of certain amaranths, as Amaranthus retroflexus.

noun

1. Also called: redroot any of several coarse North American amaranthaceous weeds of the genus Amaranthus, esp A. retroflexus, having hairy leaves and green flowers
2. a US name for fat hen