1. 
[syn: offshore, seaward]
2.  at some distance from the shore; 
- Example: "offshore oil reserves"
- Example: "an offshore island"
ADVERB (1)
1.  away from shore;  away from land; 
- Example: "cruising three miles offshore"
The Collaborative International Dictionary of English v.0.48:
Offshore \Off"shore"\, a.
   1. From the shore; as, an offshore wind; an offshore signal.
      [1913 Webster]
   2. Located in the waters near the shore; as, offshore
      drilling.
      [PJC]
   3. Operating or located in a foreign country; as, an offshore
      bank account; offshore mutual funds.
      [PJC] offside
WordNet (r) 3.0 (2006):
offshore
    adv 1: away from shore; away from land; "cruising three miles
           offshore" [ant: onshore]
    adj 1: (of winds) coming from the land; "offshore winds" [syn:
           offshore, seaward] [ant: inshore, onshore,
           seaward, shoreward]
    2: at some distance from the shore; "offshore oil reserves"; "an
       offshore island"