out-the-back/Outside ==〉 The area outside of the lineup or break line where surfers in the lineup initially observe sets of waves as they approach. Often a term used to warn other surfers in the lineup that a new set of waves is approaching. "Outside!" Same as "out-the-back" (often used by Australian surfers.)
http://en.wiktionary.org/wiki/Appendix:Glossary_of_surfing

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Note added at 18 hrs (2009-12-20 01:24:20 GMT)
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Outside - offshore (向海区 ) ; area outside the surf area(碎波帶之外)

I prefer (offshore 向海区 )

outside - 1. offshore, beyond where the waves break
3. position of surfers on the backside of the swells
http://www.krankykids.com/research/surf_slang.html

outside - offshore, beyond where the waves break
http://www.surfingvancouverisland.com/surf/lingo.htm