In days of old......never mind...er.... lets just put it this way, when I was growing up, the headstay was the stay that goes to the head of the mast. On a masthead sloop with a single headsail, the headstay is the same stay as the forestay. On a boat with multiple stays forward of the mainmast (or foremast on a schooner), the stay that is inboard of the headstay is the forestay and the stay that is inboard of that is the Jibstay. On a boat that only has two stays forward of the forward most mast, the forestay can be the jibstay. The popular term ''staysail'' is an abreviated form of the term,forestaysail. The other sail is a headstay sail. Both are headsails, as are
spinnakers which are not flown from stays at all. Baby stays are stays that are used for structural support and are of a size and location where a headsail cannot be effectively flown from it. There is no such thing as a cutter stay (except perhaps on vessels with left handed monkey wrenches.)
What happens to the sheets? If they jibe around the outside, are the sheets routed outside of the headstay as well? Yes....
Jeff