While we’re on the topic of i-stems (the dentālia, in particular), here are comparative diagrams of the English plot and Latin aratrum.
I couldn’t find two pictures that corresponding exactly, but using these two along with Lewis and Short we can offer the following definitions:
- buris, buris (m.) plow-beam: the curved hind-piece that would feature a yoke-hole for the oxen (replaced by human handles in English plow)
- tēmo, tēmōnis, (m.) plow-beam/’tongue of the plow’: the portion of the plow beam that sticks forward as the plow moves forward
(Think of it as the bow of a ship. If you need it, here’s the distinction between the prow and the bow.)
- dentālia, dentālium (n.) plow-share: the hind-wood of the plow-share
- vōmer, vōmeris (m.) plow-share: the fore-wood of the plow-share
- culter, cultrī (m.) coulter: the knife that cuts the furrow
(These three parts work together like the prow of a ship to cut a widened furrow in the field. The coulter makes the initiate cut, and the plow-share spreads this. Imagine opening a Ziploc bag… you can open it with a pencil and it will open but remain narrowly open, or you can open it with your whole hand and it will open wide.)
- aurēs, aurium (another i-stem!): the plow-ears, which further widen the furrow, and are curved to curl the dirt in an outward direction.
I’m sure this description is inadequate, and a Youtube video with a live plow would be so much more helpful. I failed to find such a video, but if anyone has seen one, please leave the link in the comments!