The Collaborative International Dictionary of English v.0.48:

Sea mew \Sea" mew`\ (Zool.)
   A gull; the mew.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Mew \Mew\, n. [AS. m?w, akin to D. meeuw, G. m["o]we, OHG. m?h,
   Icel. m[=a]r.] (Zool.)
   A gull, esp. the common British species (Larus canus);
   called also sea mew, maa, mar, mow, and cobb.
   [1913 Webster]

WordNet (r) 3.0 (2006):

sea mew
    n 1: the common gull of Eurasia and northeastern North America
         [syn: mew, mew gull, sea mew, Larus canus]