Two nouns placed next to each other make up a construct chain which is the rough equivalent of the genitive case in Greek. The first noun is said to be in the construct state; the last noun is said to be in absolute state. more | video
Note:
a noun ending in sere-yod, is always a masculine, plural noun in construct; see here
the entire construct chain is to be considered definite when the last noun is definite; see here