A skydiving jumpsuit is not simply protective clothing — its cut determines how much air a jumper catches, and therefore how fast they fall relative to others.
Matching fall rate is the point
Formation skydiving requires everyone in a group to fall at a similar speed. A lighter jumper may wear a baggier suit with more surface area to slow down; a heavier jumper may wear a tight, slick suit to fall faster.
Belly suits often have grippers — fabric handles on the arms and legs — so other jumpers can take hold. Freefly suits are cut differently again, built to withstand higher speeds and to work in multiple orientations.
These pages explain what things are so the language makes sense. They are not instruction and cannot substitute for it — skydiving is taught in person by rated instructors at a drop zone, and anything involving equipment handling or emergency procedures belongs there rather than on a web page.