The ring finger: the finger between the middle and little finger. Often the finger on which wedding rings are worn; also referenced in contexts like piano fingering.
毎朝、薬指に結婚指輪をはめる。
I put my wedding ring on my ring finger every morning.
ピアノの教則本には、薬指は『4』と書かれていることが多い。
In piano method books the ring finger is often marked as '4'.
中指をけがしているので、薬指でペンを持って書いた。
My middle finger is injured, so I held the pen with my ring finger and wrote.
The fourth toe (the toe between the middle toe and the little toe); sometimes referred to as the 'ring toe' in context.
サッカーで足の薬指を打ってしまい、歩くのがつらい。
I hit the ring toe while playing soccer and it's painful to walk.
海辺で足の薬指をぶつけて、爪が青くなった。
I banged my ring toe at the beach and the nail turned blue.