This is the 692nd most frequent Armenian word.
այդքան
"That much" or "so much."
Here 'այդքան' ('that') expresses a degree of satisfaction, specifically to a lesser extent.
Ես այդքան գոհ չէի նրանց աշխատանքից։
I wasn't that satisfied with their work.
Here 'այդքան' ('so') is used to emphasize the degree of happiness the person feels.
Ինչու ես այդքան ուրախ այսօրվա համար։
Why are you so happy about today?
Here 'այդքան' ('all that') refers to the quantity of experiences observed.