The Collaborative International Dictionary of English v.0.48:

Sewer \Sew"er\, n.
   1. One who sews, or stitches.
      [1913 Webster]

   2. (Zool.) A small tortricid moth whose larva sews together
      the edges of a leaf by means of silk; as, the apple-leaf
      sewer (Phoxopteris nubeculana)
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Sewer \Sew"er\, n. [OF. sewiere, seuwiere, ultimately fr. L. ex
   out + a derivative of aqua water; cf. OF. essevour a drain,
   essever, esseuwer, essiaver, to cause to flow, to drain, to
   flow, LL. exaquatorium a channel through which water runs
   off. Cf. Ewer, Aquarium.]
   A drain or passage to carry off water and filth under ground;
   a subterraneous channel, particularly in cities.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Sewer \Sew"er\, n. [Cf. OE. assewer, and asseour, OF. asseour,
   F. asseoir to seat, to set, L. assidere to sit by; ad +
   sedere to sit (cf. Sit); or cf. OE. sew pottage, sauce,
   boiled meat, AS. se['a]w juice, Skr. su to press out.]
   Formerly, an upper servant, or household officer, who set on
   and removed the dishes at a feast, and who also brought water
   for the hands of the guests.
   [1913 Webster]

         Then the sewer
         Poured water from a great and golden ewer,
         That from their hands to a silver caldron ran.
                                                  --Chapman.
   [1913 Webster]

WordNet (r) 3.0 (2006):

sewer
    n 1: a waste pipe that carries away sewage or surface water
         [syn: sewer, sewerage, cloaca]
    2: someone who sews; "a sewer of fine gowns"
    3: misfortune resulting in lost effort or money; "his career was
       in the gutter"; "all that work went down the sewer";
       "pensions are in the toilet" [syn: gutter, sewer,
       toilet]