Laminated glass comprises two sheets of glass sandwiched around a thin layer of (usually) polyvinyl butyral (PVB). This lamination is done under heat and pressure, making the PVB act as a glue to stick the two sheets of glass together, creating one clear pane.
Not only does laminated glass have a higher impact resistance, if one or both panes do break, the pieces of glass remain stuck to the PVB interlayer. This makes the glass both safer and more secure.
An intruder who is determined enough to keep hammering away at the glass will be able to make a hole in the PVB and may be able to get in eventually, but it will take a long time and all the hammering will create a lot of noise. Most intruders will give up when they realise the glass is laminated.
Toughened (safety) glass
Toughened glass is made in such a way that it is tougher (as the name suggests) and less likely to break than normal glass. It also is made in such a way that if it does break, it shatters into small relatively harmless pieces rather than long sharp shards.
The rules for the use of safety glass are a little complex and there are some exceptions, but the essence of these regulations is that any glass within 800mm of the floor – glass in doors and glass adjacent to doors up to 1.5m from the floor – all needs to be specified as safety glass. Safety glass in this context is generally toughened glass or laminated glass.