A B734 CREW DSNDING INTO SEA; PLANNING TO CROSS THE FIX AT 16000 FT FOR A S LNDG WAS UNABLE; AT ATC'S REQUEST; TO CROSS AT 12000 FT FOR A N LNDG. A 360 DEG TURN WAS PERFORMED TO GET INTO THE FLOW OF THINGS.

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FLYING LAX DIRECT SEATTLE AND CLRED THE 'OLYMPIA 2 ARR; DSND VIA THE OLYMPIA 2;' THERE WAS NONSTANDARD CLRNC TERMINOLOGY BY ATC AS TO WHAT ALT TO ARRIVE AT OLM FIX. WE EXPECTED TO CROSS OLM 16000 FT FOR RWY 16R AT SEA; PER OUR LATEST ATIS. CTR THOUGHT WE WERE TO CROSS OLM AT 12000 FT PER NEW ATIS AND A RWY CHANGE THAT WE WERE UNAWARE OF. IN SUMMARY: PRIOR TO OUR CLRNC LIMIT AT OLM; CTR CALLED US AND ASKED IF WE WOULD MAKE 12000 FT AT OLM. WE SAID NO; AND THOUGHT WE WERE LNDG RWY 16R TO CROSS OLM 16000 FT. CTR SAID 'NO PROB; MAKE A L 360 DEG TURN PRIOR TO OLM AND DSND TO 12000 FT VIA THE OLYMPIA 2 ARR LNDG RWY 34.' THERE WAS NO CONFLICT OR EVENT; OTHER THAN LESS THAN OPTIMUM COM BTWN CTR AND OUR AIRPLANE. CAUSE: NONSTANDARD TERMINOLOGY FOR OLYMPIA 2 ARR CLRNC. CTR DID NOT USE THE EXPECTED STANDARD CLRNC TERM 'DSND VIA THE OLYMPIA 2; CROSS AT OR 16000 FT (OR 12000 FT) LNDG S (OR N).' INSTEAD; THEY USED THE TERM 'N FLOW' WHICH I; AS A NEW FO; MISUNDERSTOOD TO MEAN FLY N ON THE 340 DEG HDG FOR LNDG RWY 16R (S). NONSTANDARD TERMINOLOGY ALONG WITH NEW FO MADE UNCLR COM.