I think it refers to the size of the company

It seems to specifically refer to structuring, as in structuring of services, supply chains, software systems, personel, etc. I found references to "dimensioning" in relation to all of these areas. Here's the clearest and most detailed reference:
Hope this helps, Kate.

The dimensioning of nursing staff according to nursing coordinators: concept, aim and use1
Luciana de Freitas CamposI; Marcia Regina Antonietto da Costa MeloII
IMS in Nursing, Professor Vales do Jequitinhonha e Mucuri Federal University, UFVJM, Brazil, e-mail: [email protected]
IIPhD Professor, University of São Paulo at Ribeirão Preto, College of Nursing, WHO Collaborating Center for Nursing Research Development, Brazil, e-mail: [email protected]
In this reality, nursing human resources demand more professionals, more cases of dismissal, hours of training and improvement, among other costs(2), which permits the interference of professionals from other specialties in their dimensioning, potentially causing legal damage to nursing and institution. Thus, qualitative and quantitative aspects of nursing personnel have attracted the attention of direct nursing service managers, due to the implications of inadequate dimensioning for the outcomes of nursing care delivery to the clientele(3).
Dimensioning constitutes "the adaptation of personnel in quantitative and qualitative terms"(4). It can be also defined by its final purpose, which is "planning the quantity of employees per category, required in order to fulfill, directly or indirectly, the patients' nursing care needs"(5).
Yet, we agree that "it is through this client/nursing relation that we can have support to justify an ideal number of nursing personnel"(6).
Considering the work load at the units under study, dimensioning is "understood as a systematic process that bases planning and evaluation of the number and quality of nursing personnel needed to provide nursing care, to guarantee the previously established quality, to a group of patients/clients, according to the organization's philosophy and structure, as well as the singularity of each service"(7).
http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0104...