Instantiating
From APIDesign
What a real world definition of instantiating could be?
Imagine you have a template and from it you can create (usually more than one) instance. Like if you have a DNA and based on it you can create few live beings of the same genofond. Initially same, but then living independently their own lives. Creating the being would be instantiating.
In object oriented class based languages (see list on wikipedia) the "class" plays the role of a template from which one can create (e.g. instantiate) many objects - initially same, but since then living on their own.