Column Type Suggestions

I am in the midst of planning for a new database which will contain specific
keywords relating to different products. For example a "Microwave" may have
the keywords HOUSEHOLD -> PANASONIC -> CAROUSEL -> CONVECTION -> 2200 WATTS.
A pair of Levis may be CLOTHING -> LEVIS -> STONEWASHED -> BOOT CUT ->
36x34.

Initially I had planned to use Postgresql's Array Column (keywords
varchar(100)[]) but this has some limitations when using the LIKE operator,
making searching for specific string of words difficult unless you know
firsthand the array key (keywords[2] LIKE 'PANA%').

Does anyone have any suggestions? Product keywords could vary from 1 up to
20, maybe more. Performance isn't a huge issue since the database table will
be fairly small and on a local network. Appreciate all the input! NOTE:
Using PHP5/Postgresql 8.3