A process is a synonym for Activity in Life Cycle Assessment terminology. In LCA practice, the term process is widely used, particularly in traditional LCA literature and software applications, whilst "activity" represents the more formal terminology adopted in standardised glossaries.
ISO 14040 clause 3.11 defines a process as the "smallest element considered in the life cycle inventory analysis for which input and output data are quantified". This corresponds to what is more precisely termed a "unit process" in the ISO standards. However, in common usage within the LCA community, "process" is often used more broadly to refer to any doing or making activity, whether it represents the smallest unit of analysis or a larger grouped activity.
The etymological root of activity comes from the Latin actio, meaning "doing or making", which captures the fundamental nature of what both terms describe. Activities (or processes) encompass all forms of doing or making, including human activities performed by humans, machines, and animals in human care, as well as environmental mechanisms that occur in nature without human intervention.
Within Life Cycle Assessment, processes are the building blocks of product systems. Each process transforms inputs into outputs through exchanges with other processes or with the environment. Understanding processes and their interconnections is essential for constructing accurate life cycle inventories and conducting meaningful environmental impact assessments.
The preference for "activity" over "process" in modern LCA glossaries reflects an effort to use clearer, more descriptive terminology that is less likely to be confused with other technical uses of the word "process" in industrial and scientific contexts.
