A grammatical expression (attached after a verb) indicating a change of state: something gradually becomes the case or someone comes to do (or stop doing) something.
毎日練習したら、ピアノが弾けるようになった。
After practicing every day, I came to be able to play the piano.
子どもは小学校に入ってから、一人で家に帰れるようになった。
After starting elementary school, my child became able to go home alone.
寒くなってきたので、水シャワーでも平気になった。
As it got colder, I became okay with cold showers.
最近忙しくて、昼ごはんを食べないようになった。
Lately I've been busy and have started not eating lunch.