Corrosion degrades the useful properties of materials and structures including strength, appearance and permeability to liquids and gases. Many structural alloys corrode merely from exposure to moisture in air, but the process can be strongly affected by exposure to certain substances. Corrosion can be concentrated locally to form a pit or crack, or it can extend across a wide area more or less uniformly corroding the surface.
foe. 1. a person who feels enmity, hatred, or malice toward another; enemy: a bitter foe. 2. a military enemy. 3. an opponent in a game or contest; adversary: a political foe. 4. a person who is opposed in feeling, principle, etc., to something: a foe to progress. 5. a thing that is harmful to or destructive of something.
Definition of formidable for English Language Learners. : 1  very powerful or strong : deserving serious attention and respect. : 2  very difficult to deal with. : 3  large or impressive in size or amount.