Forum rookie - What is stopping varnish and stopping putty?

Hello,

 I picked up a Mayflower Galeon 1:64 - Artesania Latina kit (Spain) to practice on and am not sure exactly what clear stopping varnish or what stopping putty is. Do they possible mean sanding sealer?  Can someone translate it to a US brand? I'm beginning my first wood ship model in decades and need to come up to speed. The last wood ship model my brother and I did was built from old orange crates using photographs and drawings from the library and cut out with razer blades and jewelers files. It got lost on tour by LA's Museum of Natural History back in the mid 60's. Just never got aroung to doing another until now.

-Special ed