The inverse of impedance. Usually denoted as "Y" in electrical equations, or 1/Z, Z being impedance. The unit value of admittance is commonly dubbed "mhos" (backwards spelling of ohms.) It is a measure of the lack of impedance in a circuit, system of circuits or a specific conductor. A short circuit should, ideally, have an admittance of infinity. An open circuit will have an ideal admittance of 0 mhos.
Z = 10 ohms
Y = 1/Z = 1/10 = 0.1 mhos

Student 1: What's admittance?
Student 2: I don't know. I just use 1/Z.
Student 1: Oh ok.

by core5 March 30, 2008
A combination of Admission and stupidity, often used by drunk women and college bro's
"I asked John if he slept with karen and got his Admittal!"
"Oh that's cool, I think it's probably about time you stopped drinking,"
by Androgeniousness March 29, 2010
MILITARY - A formal, professional disclosure or confession provided in the interest of integrity and transparency, admitting to having made a mistake or engaged in acts of misconduct in one's past.
In order to enlist in the United States Army, I was compelled to formally submit a "self admittal" up the chain of command explaining in detail every law enforcement encounter I had in my past, and why I still believed it would be in the Army's best interests to consider me for enlistment and acceptance dispite my criminal background discrepancies.
by ajl1776 May 3, 2018