You can put it on two computers at the same time.
thanks for your prompt help!
But both computers and or both installs of LR can not be used at the same time. Adobe allows their software to be installed on 2 different computers so the user can have it on a desktop, for home/office work, and a notebook, for when traveling or the like, or if you have 2 different locations, home and office, on 2 desktops. But they are supposed to be used by the same person and not at the same time.