Offshore has two principle meanings:
- Physical - in the sea away from the shore; not on the shoreline but out to sea.
- Financial - a relative term generally applied to low tax jurisdictions by citizens of high tax nations. Many islands are also low tax jurisdictions to encourage inward investment, hence the association with the physical meaning.
Note: some offshore centres are not in any physical respect offshore e.g. Dublin or Switzerland.
Further details can be found here: