What does "sorrel" mean?

Additional senses

1. 2.A yellowish or redish brown color.
2. 3.One of various plants having a sour juice; especially, a plant of the genus Rumex, as Rumex Acetosa, Rumex Acetosella, etc. Mountain sorrel. (Bot.) See under Mountain. -- Red sorrel. (Bot.) (a) A malvaceous plant (Hibiscus Sabdariffa) whose acid calyxes and capsules are used in the West Indies for making tarts and acid drinks. (b) A troublesome weed (Rumex Acetosella), also called sheep sorrel. -- Salt of sorrel (Chem.), binoxalate of potassa; -- so called because obtained from the juice of Rumex Acetosella, or Rumex Axetosa. -- Sorrel tree (Bot.), a small ericaceous tree (Oxydendrum arboreum) whose leaves resemble those of the peach and have a sour taste. It is common along the Alleghanies. Called also sourwood. -- Wood sorrel (Bot.), any plant of the genus Oxalis.