The term 'bellybutton type' refers to the shape of a person's NAVEL. The crossword solutions for this term are 'innie' (5 letters), 'outie' (5 letters), 'NAVEL' (5 letters), 'ADAM' (4 letters), and 'LINT' (4 letters). An 'innie' is a type of NAVEL where the center is indented, while an 'outie' is a type of NAVEL that protrudes outward. The term 'ADAM's NAVEL' is used to refer to an outie, as it is believed to be the shape of ADAM's NAVEL in the Bible. LINT is a type of fluff that can accumulate in a person's NAVEL, regardless of its shape.