Plenty of quaint monosyllabic technical terms in Scots law.
blench – the most common form of feudal tenure in the system's latter centuries, under which no or a nominal feuduty was payable.
croft – a small agricultural holding in northern or western Scotland to which the Crofting Acts apply. Determining croft status is very technical but the starting point is the precise amount of the rent in 1886.
eik /i:k/ – add-on to Confirmation (≈ Probate). I'm sure you can guess the etymology.
fee – ownership subject to a liferent.
feu /fju:/– an area of ground held of a superior under the feudal system of landownership.
flit – (of a tenant) to remove oneself from tenanted ground at the end of the tenancy.
ish – expiry date of a lease (corruption of exit, I believe).
poind /pɪnd/ (yes really) – to seize a (moveable) asset belonging to/possessed by your debtor and sell it to satisfy a debt owed to you.
seised /si:zd/ – the state of having a completed title to (i.e. being the owner of) land.
sist – to put on hold (a legal action); to bring in a new party to an action (a somewhat confusing homonymy).
tack – a lease. (OK, this is no more technical than "lease" but it is obscure.)
teind /tɛɪnd/ – a tithe exigible from a landowner for maintenance of the clergy (the obligation came with the land).
thirled – legally bound to use the mill belonging to your feudal superior to grind your flour.
Many of these are not as antiquated as you'd think. Almost all land in Scotland was held under feudal tenure under the feudal system was abolished in 2004 (no, really). Modern Scots lawyers have to use croft, eik, fee*, ish and sist on a regular basis.
Some more from bagpiping: birl, cran, grip and throw are all terms for different musical embellishments consisting of specific series of gracenotes.
Rugby also has a few: maul, ruck, scrum, touch try. Not obscure if you follow rugby but nonetheless technical, in the sense that there are detailed rules for working out when a situation falls within the definition.*We also use fee in its everyday meaning an awful lot, of course.