I live in Seattle now.
My mother grew up in Seattle.
I will send that funny picture of you to Seattle.
The name of the city (シアトル／しあとる) with a 市 attached to it means it is "the city of ____." You can do this with any city (try it out on your hometown!). Because of this, you should know that this word means Seattle, or more specifically City of Seattle.
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.