TURBOJET FLC IN CRUISE AT FL210 RECEIVE KORRY TWO ARR CLRNC AND INCORRECTLY START DESCENT.

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EN RTE ON A FLT FROM DCA TO LGA WE WERE CLRED BY WASHINGTON CTR 'CLRED DIRECT TO BESSI (INTERSECTION) CLRED KORRY TWO ARR.' WE READ BACK THE CLRNC AND PROCEEDED DIRECT TO BESSI AND THOUGHT THAT WE WERE CLRED TO DESCEND VIA THE KORRY TWO ARR; BECAUSE HE SAID 'CLRED THE KORRY TWO ARR.' WE WAITED A MIN OR SO AND THEN BEGAN TO CROSS BESSI AT OR ABOVE 17000 FT. CTLR SAID 'CONFIRM YOU ARE AT FL210.' I SAID; 'NEGATIVE; WE ARE DESCENDING VIA THE KORRY TWO AS CLRED.' CTLR SAID; 'YOU CAN NOT DESCEND UNTIL CLRED TO DESCEND VIA THE KORRY TWO ARR; JUST MAINTAIN FL190.' THE CONFUSION CAME FROM THE FACT THAT HE SAID DIRECT TO BESSI; CLRED THE KORRY TWO ARR. I HAVE NEVER BEEN CLRED AN ARR UNLESS YOU ARE CLRED TO COMPLY WITH THE ENTIRE ARR PROC. I DO UNDERSTAND THAT YOU HAVE TO BE CLRED TO DESCEND VIA; BUT I FEEL THAT THE COMS WERE MISLEADING. IT WOULD HAVE BEEN PROPER TO SAY; 'FLY DIRECT TO BESSI; THEN THE KORRY TWO ARR.' NOT; 'CLRED THE ARR;' UNTIL CLRED TO DESCEND VIA THE KORRY TWO ARR. NO LOSS OF SEPARATION OCCURRED AND WE WERE LATER CLRED TO DESCEND VIA THE KORRY TWO ARR. CONTINUED THE FLT UNEVENTFULLY AND LANDED LGA.