The Mishna on our daf teaches that anything that is known by a shem levai – a modifier or special name – will not be included in a general vow. For example,
- Someone who takes a vow not to drink wine would be allowed to drink apple wine
- Someone whose neder prohibits them from using oil would be allowed to use sesame oil
- Someone who takes upon himself not to eat vegetables can eat “vegetables of the field” (i.e. vegetables that grow wild and are not farmed)
An object gets a shem levai when an additional word is added to clarify and distinguish it from the normal use of the word. In the first two cases mentioned in our Mishna, for example, plain use of the word “wine” means wine made from grapes, not wine made from any other fruit, and plain use of the word honey means bee honey, not honey made from dates. The baraita that appears in our Gemara makes clear, however, that the basic definitions of terms depends, to a large extent, on normative word usage in a given place. Thus, in the Mishna, the plain meaning of the word “oil” is oil made from olives, not from sesame. Yet this is true only in Israel, where the Mishna was written. In Babylon, the simple meaning of “oil” was sesame oil, and olive oil was seen as having a shem levai.
This distinction is made not only with regard to differences in place, but also regarding differences in time. As we learned in the Mishna, under ordinary circumstances, non-cultivated vegetables are not considered “vegetables” as far as nedarim are concerned. During the shemita year, however, when planting is forbidden and the only available vegetables are those that grow wild, it is the yerek ha-sadeh – the vegetables of the field – that take on the simple meaning of “vegetables” when someone mentions them in a vow.