One way to hold the whole word: a tumbler is whatever tumbles. The source records the word as tumble plus -er, the one that does it. So the picture underneath every use is something going over instead of staying upright. A body turning in the air. A glass that will not stand still. Small parts dropping into place inside a lock. A drum rolling stones over and over until they shine. The learner-dictionary order puts the drinking glass first because that is the sense people meet most, but the person who turns over is the one closest to the plain meaning of the parts.
From the word’s history
The packet's Wiktionary entry records the word as tumble + -er, that is, the one that tumbles. Each family below is a different answer to the question of what is doing the tumbling: a person, the glass itself, the parts inside a lock, or the things loaded into a machine.
來源把這個字記成 tumble 加 -er，也就是「翻滾的那一個」。下面每一個家族其實是在回答同一個問題：到底是誰在翻。是人自己翻，是杯子自己倒，是鎖裡的零件落下去，還是被放進機器裡的東西在滾。
Wiktionary entry for tumbler, supplied in this packet (source_ref kaikki:3f6f69a190036ae4:525954149:41738): From tumble + -er.
登入就可以看每一支怎麼連回核心畫面。