I can't help but feel that 'unis' is a bit of a Freudian slip.
Although it's not dimensionless, my favorite is how we civil engineers often refer to pressure in units of 'head'. Literally, the height of a water column per unit area. (Analogous in concept to mm Hg) A very handy unit when you're concerned with lifting fluids/making sure they flow well after friction losses.
The typo is fixed :D
What is the atmospheric pressure in terms of heads? 10 or something?
I actually do not know off the top of my head. We often work in 'gauge pressure', setting 1 atm as the 0 point. The trivial answer I guess, is 0. Looking up the answer, it's a little over 10 1/3 m.
that is a big head :D
In hindsight, I should've known this both because it's the same as the limit for sucking water up a tube in a vacuum (at 1 atm) and the rule of thumb that pressure increases by 1 atm every 10 m.
This is why I actually suggested 10 in the very beginning. This being said, the next episode is finally out :D