http://www.faa.gov/atpubs/ATC/Chp3/atc0310.html#3-10-5
NOTE-
A clearance to land means that appropriate separation on the landing runway will be ensured. A landing clearance does not relieve the pilot from compliance with any previously issued restriction
http://www.faa.gov/atpubs/ATC/Chp3/atc0310.html#3-10-3
3-10-3. SAME RUNWAY SEPARATION
a. Separate an arriving aircraft from another aircraft using the same runway by ensuring that the arriving aircraft does not cross the landing threshold until one of the following conditions exists or unless authorized in para 3-10-10, Altitude Restricted Low Approach.
1. The other aircraft has landed and is clear of the runway. Between sunrise and sunset, if you can determine distances by reference to suitable landmarks and the other aircraft has landed, it need not be clear of the runway if the following minimum distance from the landing threshold exists: (See FIG 3-10-1.)
2. The other aircraft has departed and crossed the runway end
While it would be excellent for worldwide standardization if there was one Air Traffic Control regulation/terminology, I recognize the right for each soverign nation to apply modifications for their country's rules.
Many people find the practice "behind landing traffic, line up and wait" an unnecessary risk, especially at night, and even more so after the SD-330/MD-80 tragedy at LFPG a couple of years back.
I fly regularly out of JFK, and appreciate their talent in such a very restricted environment. However, I have to agree that they are very unprofessional with their terminology. Perhaps a word to our safety rep might fix this. Give me a few weeks to work on it before judging if there has been any improvement.