Boil the word comes from the verb boil that it means that a fluid from boiling. Example: Leave to boil milk for a while. The word grass or grass comes from the latin herba and means small plant of tender stem usually dying the same year to the seed (seed). Example: Bad grass never dies (proverb).
The Latin word herba gave heritage via grass because the vulgarisms whose first syllable had one and tonic diptongaron in ie, such as petra ( 41 stone; and as the Latin i, in old English, also wrote with and Greek as Ysabel, also admitted yerba. The Royal Spanish Academy established in 1726 that the and could only be consonant, although it followed and still admitting the two forms, herb and grass, call the herbaceous plant. That is not supported is boil, as this word is a verb conjugation form boil has another etymology.
