Amylase breaks the bond between two sugar molecules in a chain (the chain is called starch).
The type of bond is called a glycosidic bond which is just a covalent bond between sugar molecules.
The "1.4" bond you are talking about is normally written "1,4" or "1-4"; you could interpret it as "1 to 4" because it is referring to a bond involving the first and fourth carbons of the sugar (they aren't bonded directly, there is an oxygen in between); they are just numbered that way so that (bio)chemists can talk about the molecule - see this other Q&A from Chemistry about the numbering of the carbons of glucose.