NOUN (3)

1. the cost of carrying or transporting;

2. overland track between navigable waterways;

3. carrying boats and supplies overland;

The Collaborative International Dictionary of English v.0.48:

Portage \Port"age\ (?; 48), n. [From 2d Port.] (Naut.)
   (a) A sailor's wages when in port.
   (b) The amount of a sailor's wages for a voyage.
       [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Portage \Port"age\, n. [3d Port.]
   A porthole. [Obs.] --Shak.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Portage \Por"tage\, n. [F., from porter to carry. See Port to
   carry.]
   1. The act of carrying or transporting.
      [1913 Webster]

   2. The price of carriage; porterage. --Bp. Fell.
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   3. Capacity for carrying; tonnage. [Obs.] --Hakluyt.
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   4. A carry between navigable waters. See 3d Carry.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Portage \Por"tage\, v. t. & i.
   To carry (goods, boats, etc.) overland between navigable
   waters.
   [1913 Webster]

WordNet (r) 3.0 (2006):

portage
    n 1: the cost of carrying or transporting
    2: overland track between navigable waterways
    3: carrying boats and supplies overland