(medicine) Initialism of porcine intestinal adenomatosis. / Initialism of personal injury accident. / (sexuality) Initialism of penis in anus.

(obsolete) A coming forth.

Dated form of pickaback.

(aviation, space flight) An anti-G technique to increase G-tolerance and reduce G-LOC incidences, that has been described as like straining on the toilet while constipated. The technique has taught...