Aviation Dictionary
اختلاف بین دو سطح فشار متفاوت که با علامت p∆ نشان داده شده و واحد آن psid می باشد.
A single pressure(∆p) which is the difference between two opposing pressures. The resultant of a 12 psi pressure opposing a 32 psi pressure, is a 20 psi differential pressure. This is expressed as 20 psid.