Full Idea
There are no items in Whitehead's ontology called 'processes'. Rather, the term 'process' refers to the way in which the basic things - which are still events - come into existence and cease to exist. Whitehead called this 'becoming'.
Gist of Idea
In Whitehead 'processes' consist of events beginning and ending
Source
report of Alfred North Whitehead (Process and Reality [1929]) by Peter Simons - Whitehead: process and cosmology 'The mature'
Book Reference
'Routledge Companion to Metaphysics', ed/tr. Le Poidevin/Simons etc [Routledge 2012], p.185