Foresails can come in different sizes. The size of a foresail is designated by how far aft toward the mast the clew of the sail reaches. A 70% sail would only reach 70% of the way from the forestay to the mast, and a 130% sail would reach 130% past the mast, overlapping the mainsail (the actual formula is a bit more complicated).
A foresail that is 100% or less is called a jib. A sail that is more than 100% is called a genoa. However, in common usage, any size foresail is often just called a jib. The term working jib is sometimes used to specifically refer to a jib sail that is smaller than 100%.
Foresails are often numbered in decreasing order of their size. The #1 sail would be the largest genoa, and a working jib might be #3 or #4.