田徑場上的圓盤
圓盤本身，以及以它為名的比賽——器材先有，項目再借用它的名字。
noun · B2
A heavy, flat, round object, shaped like a thick plate, that athletes throw as far as they can in a sport.
鐵餅
核心畫面
One way to hold discus is as a flat round plate seen edge-on. Wide and full when you look at its face, almost a line when you turn it. Every use of the word keeps that shape: the heavy plate an athlete spins and lets go, the event named after it, and a bright fish whose body is pressed into the same disc.
discus 可以想成一個又圓又扁的盤子。正面看是完整的一個圓。轉個角度看，只剩薄薄一條線。這個形狀一直留在字裡面。…更多收起
discus 可以想成一個又圓又扁的盤子。正面看是完整的一個圓。轉個角度看，只剩薄薄一條線。這個形狀一直留在字裡面。選手手上那塊沉甸甸的圓盤，是它。丟那塊圓盤的比賽項目，也借用同一個名字。連亞馬遜那種側面圓、正面薄的魚，英文也叫牠 discus。三個用法差很遠。可是畫面都是同一個圓盤。From the word’s history
English took discus from Latin discus, itself from Ancient Greek diskos, meaning a disk, a quoit or a flat platter. It is recorded in English from 1656, and it is a doublet of dais, desk, disc, dish and disk — all of them keep some part of the flat round shape.
discus 來自拉丁文 discus，再往前是古希臘文 δίσκος，意思是圓盤、擲環或扁平的盤子，英文從一六五六年開始有紀錄。有趣的是 dais、desk、disc、dish、disk 都是同源的親戚：講餐盤的 dish、講平台的 dais、講桌面的 desk，各自留下了「又平又圓」的一部分，而 discus 留下的是整個圓盤。
Wiktionary entry for discus (kaikki extract, source_ref kaikki:3f6f69a190036ae4:1137798806), supplied in the evidence packet
Two branches
同一個形狀的魚
這一支跟運動無關，靠的是形狀：一條側面圓、正面薄的魚，長得就像那塊圓盤。
noun · C1
A freshwater fish from the Amazon whose body is round and flat from the side, like a plate standing on edge. It is often kept in home fish tanks, and the plural is usually discus.
七彩神仙魚（盤麗魚）