Not available in any store
Not available in any store is a marketing term that LEGO uses in their LEGO Direct Shop at home catalogs. Like all marketing terms, it doesn't necessarily have a specific meaning. However, the meaning that has been observed, at least in the US and UK, is that this is an item that LEGO is not making available through general retail channels. It is typically seemingly more restrictive than Hard to find.
Here are some examples of items observed to carry this tag in the past:
- Bulk pack items (such as Assorted blue plates)
- A product range (such as Scala, or Belville) not normally offered in the US (or geography of the catalog when non US) at all.
- Portions of a product range (such as Trains) that are not offered in stores in the geography (for example High speed train does not carry this tag in (at least some?) 2005 US catalogs, as you can buy it at TRU, while Burlington Northern Santa Fe locomotive does.
- A promotional product, (such as the 3442 LEGOLAND California Truck) that is developed for promotional uses (such as to be given away with a certain leval purchase) and is also sold independently.
Note that many "not available in any store" items are nevertheless available in LEGO brand retail outlets. In other words, brand retail outlets don't count as "stores" under this terminology scheme, despite being located in malls, having cash registers, etc. Toys R Us also sometimes gets such exclusive items.
"Not available in any store" does not seem to correlate with whether sets are currently in production or not.