B737-300 CREW WAS GIVEN AMBIGUOUS AND MISLEADING PHRASEOLOGY BY THE ATCT GND CTLR AT LAX.

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WE PUSHED BACK FROM GATE AT LAX AT XA30 (JUST AFTER DAWN WITH CLOUDY SKIES AND RAIN). AT APPROX XA35 WE WERE GIVEN INSTRUCTIONS TO TAXI TO TXWY E; THEN TXWY S; THEN VIA THE 'S RTE' TO RWY 7L. AS WE APCHED TXWY W ON TXWY E; WE WERE TOLD TO 'PASS THE ACR' AND I DIDN'T UNDERSTAND THE REST OF THE XMISSION. I KEYED THE MIKE AND SAID OUR CALL SIGN TO REPEAT THE CLRNC AND STOPPED MID SENTENCE AS THE CLRNC DIDN'T MAKE SENSE TO ME. LAX GND REPEATED THE SAME CLRNC. I THOUGHT HE SAID TO 'PASS THE ACR AT TXWY W.' SINCE THIS SEEMED TO BE NONSTANDARD; I THOUGHT I MIGHT HAVE MISSED SOMETHING. I STARTED OUR CALL SIGN THEN LOOKED AT THE CAPT WHO; THOUGH ALSO BAFFLED AT THE CLRNC; HEARD THE SAME THING. WE UNDERSTOOD THE CTLR TO MEAN TO PASS THE OTHER ACFT BEFORE HE ENTERED THE TXWY. THE RADIOS WERE QUITE BUSY AND SINCE WE BOTH HEARD THE SAME THING; I DID NOT ASK A THIRD TIME FOR THE CLRNC. AS WE APCHED THE INTXN; WE SAW THE OTHER ACFT XING RWY 6R AT TXWY W. WE AGAIN DISCUSSED OUR CLRNC XCOCKPIT. WE AGAIN AGREED ON WHAT WE HEARD AND BOTH ASSUMED THE CLRNC MEANT TO PASS AHEAD OF THE ACFT. IN ADDITION; WE HAD PLENTY OF CLRNC TO SAFELY PASS AHEAD OF THE OTHER ACFT. AS WE REACHED THE INTXN; GND ASKED IF WE WERE GOING TO GIVE WAY TO THE ACR. AT THAT POINT; IT WAS TOO LATE TO STOP; REASONABLY; PRIOR TO THE INTXN. I RESPONDED; NO; WE UNDERSTOOD OUR CLRNC TO BE; PASS THE ACR; MEANING WE GO FIRST. GND TOLD US NO; WE WERE SUPPOSED TO PASS BEHIND THE ACR. THEY CLRED US TO CONTINUE TO TXWY S AND THE S RTE TO RWY 7L. I APOLOGIZED ON THE RADIO AND THAT SEEMED TO BE THE END OF IT. CLRLY; THE EVENT COULD HAVE BEEN AVOIDED IF I HAD TAKEN THE RADIO TIME TO REACH BACK THE CLRNC EXACTLY AS I HEARD IT. WHETHER THE CTLR MISSPOKE OR WE MISHEARD IS; IN A WAY; IRRELEVANT. IT OBVIOUSLY PAYS TO HAVE A CLR UNDERSTANDING OF EXPECTATIONS. SUPPLEMENTAL INFO FROM ACN 499219: THOUGHT ON THIS EVENT: 1) IT WAS DARK AND RAINING AT THE TIME; AND I DID NOT KNOW WHERE 'TXWY W' WAS ALONG OUR RTE. THIS PROVED TO BE A BRIEF DISTR AND MAY HAVE CONTRIBUTED TO OUR MISUNDERSTANDING. 2) THE CTLR'S PHRASE 'PASS THE ACR AT WHISKEY' MADE SENSE; BUT BOTH THE FO AND I THOUGHT IT TO BE AN ODD CLRNC. WE BOTH ASSUMED THAT THE CTLR WAS JUST MAKING SURE WE WERE SUPPOSED TO PROCEED AND NOT STOP FOR ACR AT THE INTXN. ASSUME -- SHOULD HAVE ASKED FOR CONFIRMATION. 3) READBACK: AS I RECALL; THE FO READ BACK 'PASS THE ACR AT WHISKEY' AND WHEN THE GND CTLR DIDN'T CORRECT IT; I/WE BOTH TOOK THAT AS CONFIRMATION THAT WE'D HEARD CORRECTLY. LATER; THE FO SAID 'I DON'T THINK I READ THE CLRNC BACK; I JUST ACKNOWLEDGED IT WITH OUR CALL SIGN AND FLT NUMBER BECAUSE I WAS UNSURE OF WHAT HE INTENDED BY THE CLRNC.' WE DIDN'T DISCUSS THIS ASPECT OF THE EVENT UNTIL WELL OVER 1 HR AFTER TKOF; SO THE ONLY WAY TO BE SURE WHAT WAS SAID IS TO LISTEN TO THE ATC TAPE; UNFORTUNATELY. I DIDN'T REALIZE THAT THE FO HAD BEEN CONFUSED BY THE CLRNC -- THAT SHOULD HAVE CAUSED US TO BOTH RECONTACT THE CTLR FOR CLARIFICATION.