A Quick and Simple Dictionary

marginal

1. Adjective.  of, relating to, or located at a margin or an edge.
2. Adjective.  geographically adjacent.
3. Adjective.  written in the margin of a book.
4. Adjective.  at the lower extent of a standard.
5. Adjective.  of land that is barely productive.
6. Adjective.  (chiefly, British) of an electoral district (such as a parliamentary constituency) where the winning margin was a small proportion of the total number of votes, so that only a small change in voting behaviour is necessary to alter the outcome of an election.
7. Adjective.  of categories of people living on the social margin.
8. Noun.  Something that is marginal.
9. Noun.  Especially a constituency with a small winning margin.