common bean; green bean
Refers to the common bean (Phaseolus vulgaris), especially the immature pod eaten as a vegetable. The name comes from the fact that it can be harvested three times a year.
See also: いんげん豆
Common beans are delicious when quickly boiled and dressed.
At this time of year, the common beans in the field are growing well.
From 三度 (three times) + 豆 (bean), referring to the plant's ability to be harvested three times per year. The dialectal sense for snow pea likely arose from a similar appearance or usage.