They are the third player to throw rocks for the team. The "lead" throws the 1st and 2nd rocks, the "second" throws the 3rd and 4th rocks, the "third" throws the 5th and 6th rocks, and the "skip" throws the 7th and 8th rocks.
The third is also sometimes called the "vice skip," because the third acts as skip while the skip is throwing his (or her) rocks.
Yes
seven fifteenths
Yes.
0.5
1 and 1 fifth
I think it is 2.8.
36
2/3
There are 4 players on the ice and yoiu have a coach and usally a fifth
55/9
4 players play at one time, but there is a fifth backup player
1/5 of 2/3 is 2/15.