Middle School Student, Junior High School Student
noun
You've seen 学生 (means student). Now let's look at a student who's in the middle. Perhaps we can call this a middle school student or a junior high school student, depending on where you're from.
ちゅうがくせい
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.
私の子は、今中学生です。
My child is a junior high school student now.
これは中学生のときの作文です。
This is an essay I wrote when I was in junior high.
中学生向けのピアノのコンクールに出ました。
I participated in a piano competition for junior high school students.
大山先生は、中学生の時の先生です。
Oyama-sensei is my teacher from when I was a junior high school student.