(1) Qadr means predestination, fate or destiny. In Islam it is a necessary belief to have that God knows the fate of all creatures. It is also believed that people's lives and actions are determined by God (to some extent). Most Muslims believe in a mixture of both fate and free-will for all creatures.
(2) Qadr can also mean power or potential.

There is a Surah (Chapter) in the Quran that is known as Al-Qadr.
In the name of Allah, Most Gracious, Most Merciful
[97.1] Surely We revealed it on the grand night. (The night of Qadr)
[97.2] And what will make you comprehend what the grand night
[97.3] The grand night is better than a thousand months.
[97.4] The angels and Gibreel descend in it by the permission of their Lord for every affair,
[97.5] Peace! it is till the break of the morning.