Lessons or classes (e.g., music, sports, calligraphy) — an activity one learns or takes lessons in.
子どもの習い事でピアノを習わせている家庭が多い。
Many families have their children take piano lessons.
忙しくて今は新しい習い事を始める時間がない。
I'm busy now and don't have time to start a new class.
習い事での継続が上達の鍵だ。
Continuing with lessons is the key to improvement.