rotoscythe
/ˈrəʊtə(ʊ)sʌɪð/(also rotascythe) Now rare
noun
A lawnmower with rotating blades, designed to cut long grass or vegetation.
- The rotoscythe was the first successful design of rotary mower..
Origin
1930s; earliest use found in Implement & Machinery Review. From roto- + scythe.