means A soft, spongy confection made from sugar, water, and gelatin, traditionally eaten on its own or toasted over a fire.

from Originally literal: the marsh-mallow (Althaea officinalis) is a real plant that grows in marshes, and its name combines Old English 'mersc' (marsh) with 'mealwe' (mallow), the plant family. Centuries ago, the root's sticky sap was boiled with sugar to make a soothing medicinal sweet — so the original marshmallows really did come from the marsh. Modern versions dropped the plant entirely, keeping only the name as a fossil of their swampy origin.