Video: Any handyman worth his salt should know the difference between cement, concrete and mortar. I am not that handyman. They're all just grey sludge to me. But This Old House explains the difference between the three in a very easy to understand way. Cement is a fine powder that hardens when mixed with water and is used in many building mixes. Concrete is a mix of cement, sand and coarse stone. When wet, it's pretty thin. Mortar is a mix of cement, sand and limestone and it's much thicker than concrete. Mortar is used to hold things like bricks and stones together.
I'm probably going to forget all that and just ask the guy who works at Bunnings the next (first) time I need cement, concrete or mortar but hey, the more you know.