This is the 165th most frequent Icelandic word.
tveggja
"Of two" or "two's" (genitive plural form of "tveir," meaning "two").
Here, "tveggja" is in the genitive plural form, used to express possession or measure of 'two hours'.
Það tekur mig tveggja klukkustunda að keyra þangað.
It takes me two hours to drive there.
"Tveggja" is in the genitive plural to indicate 'two' as it relates to ownership of 'dogs'.
Hún er eigandi tveggja hunda.
She is the owner of two dogs.
In this sentence, "tveggja" describes 'a bed for two people' in a genitive plural possessive construction.