1. overplate - Noun
2. overplate - Verb
In armour, a large pauldron protecting the shoulder, or a cubitiere protecting the elbow.
A layer of metal that covers an undercoat.
A flat protective sheet that covers something
(geology) A tectonic plate that has moved over and covered another tectonic plate.
To form an overplate.
(geology, of a tectonic plate) To move on top of and cover another tectonic plate.
To form an overly thick plate on top of something.
Source: en.wiktionary.org