Wiktionary
a. (context idiomatic English) well-informed concerning.
WordNet
adj. being up to particular standard or level especially in being up to date in knowledge; "kept abreast of the latest developments"; "constant revision keeps the book au courant"; "always au fait on the latest events"; "up on the news" [syn: abreast of(p), au courant, au fait, up on(p)]
Usage examples of "up on".
I sit up on the couch and speak slowly, being careful, like I'm guiding her through this thing.
It must have been the Russian he had picked up on the eastern front.
He thought he might just take her up on the offer made by her soft brown eyes, perhaps at some time in the not too distant future.
I have been studying up on modern systems ever since I came out of rejuvenation.
He merely sat up on his four rearmost limbs and watched McKeon closely.
Nimitz stretched and ambled down from his rest to curl up on her stomach, and this time she cooed to him and stroked his fur as he laid his jaw on her breastbone to help her think.
A male voice, a bit shaken but authoritative for all that, came up on the speakers.
She flipped up on her side relative to the Aggressor wall of battle, interposing her belly impeller bands just as the first Aggressor energy weapons began to fire.
One by one the crew members called to the EVA controller up on the bridge.
All he needed was a little grooming, an occasional wrestling bout, a perch on her shoulder or lap while she pored over the book chips and to sleep curled neatly up on her pillow, and he was happy.
Soon the turquoise coloured stop signal lit up on the control panel.
I had to roll to the side, flopping onto my back, and push myself up on shaky elbows.