An acid-base indicator which is colorless in acid solution, but turns pink to red as the solution becomes alkaline. It is used medicinally as a cathartic.
Martello tower
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A building of masonry, generally circular, usually erected onthe seacoast, with a gun on the summit mounted on a traversingplatform, so as to be fired in any direction.
Martello tower meaning & definition 1 of Martello tower.
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