會轉的平台本身
這一家就是核心：還沒被指定用途的那塊圓平台。
noun · B2
A flat round surface that turns around its centre, so that whatever is placed on it can be moved to face a different way without being picked up.
旋轉盤
核心畫面
The word says its own picture: turn plus table, a flat round surface that goes round. Put something on it and you can change which way that thing faces without lifting it or walking round it. A dish in a microwave, a plate of shrimp on a big dinner table, a vase in front of a camera, a record, a train engine — the object changes size and the job changes, but the platform underneath is always the same idea.
這個字自己就把畫面講出來了：turn（轉）加上 table（平面），一塊會轉的圓形平台。東西放上去，不用抬起來、也不…更多收起
這個字自己就把畫面講出來了：turn（轉）加上 table（平面），一塊會轉的圓形平台。東西放上去，不用抬起來、也不用繞過去，就能換方向。微波爐裡的盤子、圓桌上的那盤蝦、鏡頭前的花瓶、一張唱片、一台火車頭——東西的大小和用途一直在變，底下那塊會轉的平台卻是同一個想法。From the word’s history
Wiktionary gives the whole origin as turn plus table, so the compound has always meant exactly what its two parts say. That is why the general platform, and not the record player, is the sense the others sit on.
字典記的來源就是 turn 加 table，兩個部分合起來是什麼意思，這個字就是什麼意思。所以最基礎的那一層是「一般會轉的平台」，唱盤和轉車台都是這塊平台被派去做某一件事。
Wiktionary entry for turntable, supplied in this batch's evidence packet: From turn + table.
Three branches
放唱片的那一面
把那塊會轉的平台縮小，放進唱機裡，讓它帶著唱片轉；後來這個名字又從零件擴大到整台機器。
noun · B2
The flat round part of a record player that holds a record and spins it at a steady speed while it plays.
唱盤
把車頭調頭的大圓盤
同一塊平台放大到能承載一台火車頭，嵌進地面的圓坑裡，轉半圈就把車頭調了方向。
noun · B2
A large flat round platform set into a pit in the ground, used to turn a railway engine, a carriage or another vehicle so that it faces the other way.
轉車台