Search Result for "sea level":
Wordnet 3.0

NOUN (1)

1. level of the ocean's surface (especially that halfway between mean high and low tide); used as a standard in reckoning land elevation or sea depth; 



The Collaborative International Dictionary of English v.0.48:

Sea level \Sea" lev"el\
   The level of the surface of the sea; any surface on the same
   level with the sea.
   [1913 Webster] Sealgh


WordNet (r) 3.0 (2006):

sea level
    n 1: level of the ocean's surface (especially that halfway
         between mean high and low tide); used as a standard in
         reckoning land elevation or sea depth