Land Use selections for vacant land only

I'm a Prycd and Data Tree newbie, so this may seem obvious, but I do not want to assume. I would like to confirm which selections under Data Tree Filters Land Use are for vacant land only, i.e. Vacant Land (Nec)? Also, what does (Nec) mean? Do any of the other selections inherently assume vacant land, i.e. Agricultural (Nec), Recreational Acreage, Ranch, Residential lot, Multi Family Acreage, etc?

Or, are they all considered vacant land because I am on the "Land" research page?

Thanks.