This is the 4659th most frequent Japanese word.
握り
"握り" (nigiri) means "grip" or "hold," and it can also refer to "hand-formed sushi."
Here, 『握り』 is used as the verb 『握る』 implying the act of gripping or forming sushi by hand.
彼は寿司を握るのが上手です。
He is skilled at making sushi by hand.
In this sentence, 『握り』 refers to the hand-formed sushi pieces, a specific kind of sushi preparation.
寿司の握りが好きです。
I like sushi pieces made by hand.
Here, 『握り』 as the base verb 『握る』 highlights the action of gripping or holding tightly.