Definition of "castellation" in English

noun

1. (uncountable) The act or process of making a building into a castle.

2. (uncountable) The addition of battlements to a building, as for example when a feudal manor house needed fortification against border-raider attacks.

3. (countable) Any of a set of slots or grooves in an object, often machined into a metal part, as for example on a castellated nut.