訓 よ,よん,よっ(つ) ・ 音 シ
漢越音: tứ
A box 囗 with a pair of legs 儿 trapped inside, hemmed in by four walls. Picture someone boxed in on all four sides.
Stroke data: KanjiVG (CC BY-SA 3.0) — kanjivg.tagaini.net
家族は四人です。 (かぞくはよにんです)
There are four people in my family.