A hard wooden pin used for fastening timbers together.
（钉木料用的）木钉，木栓
Example sentencesExamples
The timbers are often cut and dressed by hand, jointed and interlocked in the traditional way, and fastened throughout with wood pegs called trunnels, or ‘tree nails.’
We have used tree nails (trunnels) for frame fixing, stone ballast, and hand made rope stropped blocks.
The Slavic tradition of Viking ship building such as from Northern Poland owes a lot to the trenail, and less to the use of iron.
Boring holes in oak ships' timbers for the wooden pegs (treenails) or iron bolts required long augers of high strength.
Surprisingly to me, the old bridge didn't have trunnels, it was all bolted.
Definition of treenail in US English:
treenail
noun
A trunnel.
Example sentencesExamples
They were used for boring holes in the oak timbers that formed the frames of ships, preparatory to fastening those timbers together with iron bolts or with treenails.
Aside from that, his construction appears to be the same except when he writes, ‘parts are clamped together by treenails or screw bolts…
The new boat was built at Laleham by carpenters and locksmiths, and the materials which they used included 150 planks, presumably of oak, 900 rivets, and 900 nails, of which 500 were of wood and evidently treenails used for the frame.