demonstrative adjective, referring to a thing or a person: that, which, who.
Usage note: a preceding comma may alter the meaning of a clause starting with a demonstrative adjective.
De jonge vrouw, die de schoen past, zal ik huwen vs. De jonge vrouw die de schoen past, zal ik huwen: the young woman, whom the shoe (incidentally) fits, I will marry, vs. the (first) young woman whom the shoe fits I will marry.