The Jargon File (version 4.4.7, 29 Dec 2003):

dentro
 /den'troh/

    [demoscene] Combination of demo (sense 4) and intro. Other name
    mixings include intmo, dentmo etc. and are used usually when the authors
    are not quite sure whether the program is a demo or an intro.
    Special-purpose coinages like wedtro (some member of a group got married),
    invtro (invitation intro) etc. have also been sighted.