Work analysis is the detailed analysis of a job concerning the conditions, reqiurements and tasks of the job holder as well as the means and tools to perform the tasks. The collected data are typically used for process optmisation, health and safety improvements, or creating job descriptions.
The methods encompass a range from technical or task oriented approaches to more worker oriented procedures with a focus on skills and competencies.
Job analysis is often uses synonymously although "job analysis" can be unsderstood as an approach that is focused on single jobs while "work analysis" takes a broader view and examines the job in it's organisational and social contexts.
See: Wilson et al (2013) p. xxii