UBS Dictionary of the Greek New Testament

Sense 1: mustard plant

Semantic entry: 3.20

Semantic domains: Plants

Subdomains: Plants That Are Not Trees

Definition: mustard plant, a large herb noted for its very small seeds and in some instances growing to a height of three meters (about ten feet)

Notes: Note that in OET MAT 13:31 (and in the parallel passage OET LUK 13:19) σίναπι is actually spoken of as a δένδρον tree, evidently a type of rhetorical hyperbole.|Though the mustard plant may not be known in certain areas of the world, the use of mustard as a condiment is widely known, and therefore it is often possible to speak of ‘a plant that produces mustard’ or ‘the plant used in making mustard.’ In order, however, to make the parable meaningful, it may be necessary to have some explanation of this plant in a footnote or glossary.

Further resources: flora:3.5.8