linux kernel : processes
A process is usually defined as an instance of a program in execution; thus, if 12 users are running vi at once, there are 12 separate processes ( although they can share the SAME executable code).
Processes areoften called tasks or threads in the Linux source code.
excerpted from :Understanding the Linux Kernel, 3rd Edition
By Daniel P. Bovet, Marco Cesati, ch.3, page 79.