Picture a person with their heels lifted, only the front of the foot touching the floor. Two things happen at the same time in that one posture: the person gets a little taller, and the person gets a lot quieter. Every use of the word can be thought of as one of those two results. Reaching a high shelf or seeing over a crowd is the taller side. Crossing a room without waking anyone is the quieter side.
Wiktionary records the word as Middle English tipto, equal to tip plus toe, formed the same way as fingertip. The modern uses all sit on that literal picture: the tip of the toe.
Wiktionary 記的來源是中古英語 tipto，等於 tip（尖端）加 toe（腳趾），組法跟 fingertip（指尖）一樣。所以現在的用法都還貼在這個字面畫面上：腳趾的尖端。
Wiktionary etymology supplied in the evidence packet (kaikki:3f6f69a190036ae4:962030383): From Middle English tipto, typto; equivalent to tip + toe. Compare fingertip.
Two branches
安靜地走：不想被聽見
這一組取的是核心畫面的「輕」這一邊。腳跟不落地，地板就不響，所以整組用法背後都有一個不想驚動的人。
verb · B1
To walk with your heels lifted off the ground, so that only the front part of your feet touches the floor and your steps make almost no sound. People walk like this when there is someone they do not want to wake, disturb, or let know they are there.
踮腳走、躡手躡腳走
踮高：腳尖與高度
這一組取的是核心畫面的「高」這一邊，也保留了最字面的部位。腳跟一離地，人就多了幾公分，看得到、拿得到原本構不著的東西。
noun · B1
If you stand, walk, or reach on tiptoe, you keep your heels off the ground and put your weight on your toes. People do this for one of two reasons: to make themselves a little taller, so they can see or reach something, or to move so quietly that nobody hears them.
踮著腳（站或走）