Admittedly means as has to be granted before the main point. You concede something, and then carry on.
It is a signal of what is coming, since almost every sentence beginning with admittedly contains a but somewhere later. That is its entire function in argument, and using it well makes you sound fair rather than weak. It usually opens a sentence with a comma. Granted and it is true that do the same job. The verb admit carries the same idea of conceding, and admission is the noun for that.
1adverbadmittedlyUsed to concede a point before making a contrary one.
“Admittedly, the price is high, but it will last for years.”
From admitted + -ly.
Etymology from Wiktionary, CC BY-SA