Triple intergal

In calculus, the integral of a function is an extension of the concept of a sum. The process of finding integrals is called integration.

http://en.wikipedia.org/wiki/Integral
you can think an integral as an area/region/space/etc

integrate - verb
e.g. we integrate the function f(x) from a to b

for triple integral, it means that 3 dimensions are need to be "sum" (or integrated).
here show the detail of triple integral
http://mathworld.wolfram.com/TripleIntegral.html
f(x,y,z) is a function of 3 parameters, the triple integral means the "sum" region/space with respect to x, y and z

note: the order of integrals can be changed, ie. you can integrate f(x,y,z) with x first or with y first.