I am the site owner. There are many teams and team leaders. Site owner (Me)>Team leaders > team members. I want to give permission to team leaders to define permissions to the members. for example : One member will got READ, one member will got RESTRICTED READ. Team leader will change the effect .I am searching the name of this level. I will give this level to team leaders to manage their team.
There is no level at all (only if you want to grant permission to single users as M.Qassas described it).
In your case I suggest to use groups. Groups can be managed by the owner of the group, which can be also another SharePoint group.
This way you can construct a hierarchy for permissions without giving the ability to grant single users permissions on the site.
As you already have a logical structure of your hierarchy you only need to implement it in your SharePoint site.
First you should create a group (e.g. "Permission Administrators") which will be able to manage the "[Department] Team-Leader" groups.
This group will be set as owner of all the aforementioned teamleader groups.
Then you need to create your "[Department] Team-Member" groups and declare the appropiate teamleader group as owner of these groups.
This way you are able to control who can grant permissions to teamleaders who will be able to grant permissions to their teams.
Hope it helps.
PS: When you want to change the owner of already existing groups, you need to open the settings of the group where you will be able to change the owner and manage the permission levels.