I am reading some text at this url:

<https://cs.senecac.on.ca/~btp100/pages/content/varia_p.html>

In the section 'Qualifiers', they say:

"We can qualify the int type to be sure that it contains a minimum number of bits"
....
A short contains at least 16 bits:
....

I don't understand this, what does "qualify the int type" mean and why "A short contains at least 16 bits".

Can anybody elaborate on this please?
Thanks all.