Definition of "orach"

The saltbush: any of several plants of the genus Atriplex

1. especially Atriplex hortensis  examples

2. or Atriplex patula, found in dry habitats, that have edible leaves resembling spinach.  examples

(dated) Lamb's quarters: frost-blite (Chenopodium album) or another plant of the genus Chenopodium.  examples