First Place, First Rank
noun, の adjective
When you are number one in rank, you're in first place.
いちい
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.
一位になったら、一週間毎日カレーを作ってあげる。
If you get first place, I'll make you curry every day for a week.
妹がピアノコンクールで一位をとりました。
My sister took first place in the piano competition.
お母さん！僕、あのテストで滅茶苦茶良い点をとったんだよ！なんとクラスで一位だったんだ！
Mom! I really aced that test! I ranked at the top of my class!