名詞 rotary:

1. a road junction at which traffic streams circularly around a central island
   同義詞：traffic circle, circle, roundabout
2. electrical converter consisting of a synchronous machine that converts alternating to direct current or vice versa
   同義詞：synchronous converter, rotary converter

形容詞 rotary:

1. relating to or characterized by rotation
2. marked by or moving in a circle
   同義詞：circular

1. A device for transmitting rotary motion, consisting of a handle or arm attached at right angles to a shaft.
   曲柄一個傳遞轉動的部件，包括一個手柄或把手與一個軸直角相連
2. The gardener asked me for a rotary lawn mower.
   園丁向我要一臺旋轉式割草機。

ro.ta.ry

adj.（形容詞）
Of, relating to, causing, or characterized by rotation, especially axial rotation.
旋轉的，轉動的：屬于、有關、引起或以轉動為特征的，尤指繞軸轉動
n.（名詞）
【復數】 ro.ta.ries
A part or device that rotates around an axis.
繞軸旋轉的部件或裝置
A traffic circle.
環(huán)形交叉，環(huán)形交通樞紐

來源：
Medieval Latin rot3rius
中世紀拉丁語 rot3rius
from Latin rota [wheel] * see ret-
源自 拉丁語 rota [輪子] *參見 ret-