This is the 495th most frequent Icelandic word.
þessara
"Þessara" is the genitive plural form of "þessi," meaning "of these."
The word 'þessara' is used in the genitive plural to indicate relationship or possession with 'bóka' (books).
Ég þarf að velja á milli þessara bóka.
I need to choose between these books.
Here, 'þessara' demonstrates genitive plural agreement with 'blóma' (flowers), indicating possession.
Litir þessara blóma eru svo fallegir.
The colors of these flowers are so beautiful.
In this context, 'þessara' is in the genitive plural matching 'hluta' (things), and shows objects of care or attention.