Definitions

1. noun

A plant of the genus Ambrosia, especially Ambrosia artemisiifolia, whose seeds may cause skin irritation in some people.

“The field was covered in sheepweed, and the hikers tried to avoid it.”

2. noun

Any of several plants of the family Asteraceae, similar to ragweed, that produce allergenic pollen.

“The doctor warned the patient about the effects of sheepweed on her allergies.”