I have a field with multiple entries and I would like to extract the last entry to a new field. Does anyone have an example script to do this? Each entry is only one word so a script to extract and copy the last word would also be fine.

I can find plenty on copying first words or using just the first entry of a list in Scripts but nothing on this.
I expect it would need some kind of an array but I just can't see what the command for last entry is
Thanks!

An array is what you need, yes. Instantiate an array by splitting the field content on the entry separator. Then each element in the array is an entry, and it's a simple matter to retrieve the last (or first) one.

function Example()
{
	/*
	Get box content as string.
	*/
	var fieldValue = Form.boxes("myBox").content; // get field content
	/*
	Create array by splitting string on entrySeparator character.
	*/
	var entries = fieldValue.split(Application.entrySeparator);
	/*
	Array elements are retrieved with a zero-based count,
	so the first element is entries[0] and the last element
	is entries[entries.length - 1].
	*/
	var lastEntry = entries[entries.length - 1]; 
	/* 
	Do something with last entry...
	*/
	Application.message("Last entry is '" + lastEntry +"'");
	
}