外: outside; foreign; other; external. JLPT N5; 5 strokes.
外 indicates what is outside: the outside, foreign land, what is different or excluded.
On readings: ガイ in 外国 (がいこく, foreign country), 外国人 (がいこくじん, foreigner), 海外 (かいがい, abroad), 以外 (いがい, except, outside of), 例外 (れいがい, exception), 外出 (がいしゅつ, exit). ゲ is rare: 外科 (げか, surgery), 外科医 (げかい, surgeon).
Kun readings: そと, "outside" (外で遊ぶ, to play outside; 外側=そとがわ, external side). ほか, "other": その外 (そのほか, the rest, others); in this sense it is more often written 他 or in hiragana. はずす (外す, to remove, to detach) is transitive; はずれる (外れる, to detach; to miss the target) is intransitive, as in 町外れ (まちはずれ, periphery).
Remember: 以外 (いがい, except) and 意外 (いがい, unexpected) are read the same way but have different meanings.
外で遊びましょう。
soto de asobimashou.
Let's play outside.
Follow the steps in order. Each new stroke is highlighted.
Stroke paths: KanjiVG, CC BY-SA 3.0. Sequential diagrams derived from the original paths.