Unlimited is a word that many web hosts use saying that they will provide you with ‘unlimited disk space’ or ‘unlimited bandwidth’. The real meaning differs from host to host. When they say ‘unlimited’, they consider that they are just trying to impress you.

In reality, they are destructing the meaning of the term ‘unlimited’.
When the web hosting provider says that you can use unlimited disk space, they mean you have unlimited disk space offered but you cannot use it at the same point of time. You will be restricted if you exceed the limit offered on per-day basis. The web hosting provider is the only one who can decide the amount of space you can use.
We can say that the web host has been cleverly tempting you to host with the company without specifying the terms and conditions.
Even if they provide you with unlimited web space, they will restrict you after some limit. The main reason behind this is that if all the users utilize this unlimited space, then the web hosting company will have to invest a bigger amount of money to provide its users with unlimited space.
If you look at their terms and conditions, you will come to know about all the restrictions they put for using the free space. But the one that specifies the real amount of disk space that can be used is the one who will not restrict you and you can use your space in any way you want.
“Terabyte” is nothing but “Unlimited” 
Hosts try the best way to tempt you with their schemes and as you know the unlimited scheme has now lost the trust with the users, they are using the new term ‘Terabytes’. However, the terms and condition are still the same. It is just another attempt of the hosts to tempt you by using new terms for the same conditions.
But not All Unlimited is Doubtful
Let me tell you that not all web hosting (interesting to know is that the Danish term is webhotel) companies who advertise this unlimited scheme might fool you. That is, they really provide you with all the features they advertise. However, the other hosts who do not allow you to use such features at once restrict these features. So whenever you see an unlimited scheme, make yourself clear with the scheme by reading all the terms and conditions or the reviews of the webmasters who will guide you and will be the best help in choosing the package.
Conclusion
To conclude with, I would advise you never to accept the terms and conditions of the web hosting provider without reading them. Always read the fine printed part. Keep in mind that those fine printed instructions are the most important ones. Whenever it comes to space and bandwidth, make sure that they do not restrict you, or else it will affect your website. Also, there will be lots of restrictions that you will face when you want to use the space or when you want to use images or videos.